High strength aluminum alloys

ABSTRACT

The invention is a class of new 6XXX series high strength aluminum alloys with a fine grain structure and methods of manufacture and extrusion. Aluminum alloys of the invention comprise from about 0.90 percent to about 1.2 percent by weight silicon, up to about 0.5 percent by weight iron, from about 0.05 percent to about 0.3 percent by weight copper, up to about 0.75 percent by weight manganese, from about 0.70 percent to about 1.0 percent by weight magnesium, up to about 0.25 percent by weight chromium, up to about 0.05 percent by weight zinc, up to about 0.1 percent by weight titanium, with the balance consisting essentially of aluminum. The alloys are cast and homogenized, then extruded, quenched and artificially aged to produce a fine grain crystallization in the final aluminum product exhibiting superior yield strength and elongation properties.

CROSS-REFERENCE TO RELATED APPLICATIONS

This U.S. Non-Provisional application claims the benefit of priorityfrom International PCT Application No. PCT/US2015/019867, filed Mar. 11,2015, entitled, “HIGH STRENGTH ALUMINUM ALLOYS”, which claims thebenefit of priority from U.S. Provisional Patent Application No.61/951,309, filed Mar. 11, 2014, entitled, “HIGH STRENGTH 6XXX ALLOY(HS6X)”, and claims the benefit of priority from U.S. Provisional PatentApplication No. 61/954,358, filed Mar. 17, 2014, entitled, “HIGHSTRENGTH 6XXX ALLOY (HS6X)”, each of which is incorporated here byreference in its entirety.

FIELD OF THE INVENTION

The present disclosure is generally directed to new high strengthaluminum alloys, more particularly 6XXX series aluminum alloys andmethods of manufacturing the same.

BACKGROUND OF THE INVENTION

Automotive industries are moving towards pieces for their vehiclesextruded with aluminum rather than having steel components due to thelower weight of aluminum. The lower weight makes fuel economy betterwhich is required by CAFE (Corporate Average Fuel Economy) regulations.The movement from steel to aluminum has caused the demand for highstrength alloys to increase significantly. Typically, a 7XXX aluminumalloy would be used because of the increased strength. However, 7XXXalloys are expensive to cast, take time to extrude and additional timeto age to full strength—factors that increase the cost to customers.

High strength alloys increase the potential for thinner extrusions andincrease opportunities for reducing weight. Alloys with promisingtensile yield strength results may nonetheless exhibit lower thandesired elongation. Elongation can be improved by avoiding a mixed grainstructure of unrecrystallized and coarse recrystallized grains andinstead creating a fully recrystallized fine grain structure.

Therefore, there is a need for new high strength aluminum alloys thatreduce the expenses and efforts associated with manufacture of 7XXXalloys. There is a need for new 6XXX series aluminum alloys to reducethe expenses and efforts associated with manufacture of 7XXX alloys.There is a need for new 6XXX series aluminum alloys exhibiting highstrength with a recrystallized fine grain structure.

SUMMARY OF THE INVENTION

The invention relates to a class of new 6XXX series high strengthaluminum alloys with a fine grain structure and methods of manufactureand extrusion. Inventive aluminum alloys of the invention comprise fromabout 0.90 percent to about 1.2 percent by weight silicon, up to about0.5 percent by weight iron, from about 0.05 percent to about 0.3 percentby weight copper, up to about 0.75 percent by weight manganese, fromabout 0.70 percent to about 1.0 percent by weight magnesium, up to about0.25 percent by weight chromium, up to about 0.05 percent by weightzinc, up to about 0.1 percent by weight titanium, with the balanceconsisting essentially of aluminum.

It is one object of the invention to provide an aluminum alloy that iscast as an ingot and homogenized to uniformly disperse the variouselements. It is another object of the invention to extrude the castaluminum through a press at an initial billet temperature and at aparticular extrusion speed. It is another object of the invention toquench the aluminum material after it has been extruded through thepress. In another aspect, a method of forming an extrusion having arecrystallized grain structure is disclosed, the extrusion having athickness ranging from about 0.050 inch to about 0.500 inch.

One object of the invention is to artificially age the extruded aluminummaterial and produce a fine grain structure in the final aluminumproduct which exhibits superior yield strength and elongationproperties. One object of the invention is to provide an aluminum alloywith a minimum tensile yield strength of about 320 MPa.

It is one object of the invention to provide a high strength aluminumalloy that is a suitable substitute for 7XXX series aluminum alloys forautomotive development.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 of the drawings is a schematic cross section of an aluminumextrusion (section 569310).

FIG. 2 of the drawings is a schematic cross section of an aluminumextrusion (section 569510)

FIG. 3 of the drawings is a graphic representation of water quench ratefor various charges of aluminum extrusion section 569310.

FIG. 4 of the drawings is a graphic representation of water quench ratefor various charges of aluminum extrusion section 569510.

FIG. 5 of the drawings depicts locations for tensile testing of aluminumextrusion section 569310.

FIG. 6 of the drawings depicts locations for tensile testing of aluminumextrusion section 569510.

FIG. 7 of the drawings is a graphic representation of aluminum extrusionsection 569310 natural age ultimate tensile strength against age time.

FIG. 8 of the drawings is a graphic representation of aluminum extrusionsection 569310 natural age yield strength against age time.

FIG. 9 of the drawings is a graphic representation of aluminum extrusionsection 569310 natural age elongation against age time.

FIG. 10 of the drawings is a graphic representation of aluminumextrusion section 569310 artificial age ultimate tensile strengthagainst age time.

FIG. 11 of the drawings is a graphic representation of aluminumextrusion section 569310 artificial age yield strength against age time.

FIG. 12 of the drawings is a graphic representation of aluminumextrusion section 569310 artificial age elongation against age time.

FIG. 13 of the drawings is a graphic representation of aluminumextrusion section 569510 artificial age ultimate tensile strengthagainst age time.

FIG. 14 of the drawings is a graphic representation of aluminumextrusion section 569510 artificial age yield strength against age time.

FIG. 15 of the drawings is a graphic representation of aluminumextrusion section 569510 artificial age elongation against age time.

FIG. 16A of the drawings is a photomicrograph of a polished section ofan aluminum alloy log of the invention (head, center at 200×magnification).

FIG. 16B of the drawings is a photomicrograph of a polished section ofan aluminum alloy log of the invention (head, center at 500×magnification).

FIG. 17 of the drawings is a photomicrograph of a polished section of analuminum alloy log of the invention (head, edge at 100× magnification).

FIG. 18A of the drawings is a photomicrograph of a polished section ofan aluminum alloy log of the invention (butt, center at 200×magnification).

FIG. 18B of the drawings is a photomicrograph of a polished section ofan aluminum alloy log of the invention (butt, center at 500×magnification).

FIG. 19 of the drawings is a photomicrograph of a polished section of analuminum alloy log of the invention (butt, edge at 50× magnification).

FIG. 20 of the drawings is a photomicrograph of a polished andelectrolytically etched section of an aluminum alloy log of theinvention (head, center, at 50× magnification).

FIG. 21 of the drawings is a photomicrograph of a polished andelectrolytically etched section of an aluminum alloy log of theinvention (head, edge).

FIG. 22 of the drawings is a photomicrograph of a polished andelectrolytically etched section of an aluminum alloy log of theinvention (butt, center at 50× magnification)

FIG. 23 of the drawings is a photomicrograph of a polished andelectrolytically etched section of an aluminum alloy log of theinvention (butt, edge)

FIG. 24 of the drawings is a photograph of a cross section of aluminumextrusion section 569310 showing unrecrystallized regions.

FIG. 25 of the drawings is a photograph of a cross section of aluminumextrusion section 569310 showing unrecrystallized regions.

FIG. 26 of the drawings is a photograph of a cross section of aluminumextrusion section 569510 showing fine grain recrystallization.

FIG. 27 of the drawings is a photograph of a cross section of aluminumextrusion section 569510 showing fine grain recrystallization.

FIG. 28 of the drawings is a photograph of an electrolytically etchedcross section of aluminum extrusion section 569310 showingunrecrystallized regions with coarse grain recrystallization.

FIG. 29 of the drawings is a photograph of an electrolytically etchedcross section of aluminum extrusion section 569510 showing fullyrecrystallized grain structure.

FIG. 30 of the drawings is a photograph of a transverse weld of aluminumextrusion section 569510.

FIG. 31 of the drawings is a photograph of a weld of aluminum extrusionsection 569310.

FIG. 32 of the drawings is a schematic of the die design for section569310.

FIG. 33 of the drawings is a schematic of the die design for section569510.

FIG. 34 of the drawings is a graphic representation of yield strengthagainst extrusion exit temperature for various charges of aluminumextrusion section 569310 artificially aged at 338/347° F. for six hours.

DETAILED DESCRIPTION OF THE INVENTION

Embodiments of the present invention relate to high strength 6XXX seriesalloys comprising aluminum and additional elements. The alloys are castinto ingots and then heated or homogenized at a particular temperaturerange to uniformly disperse the alloying additions throughout thealuminum matrix. A billet of the inventive aluminum alloy is thenextruded through a press at an initial billet temperature and at aparticular extrusion speed, after which the resulting extruded aluminumproduct is quenched. The extrusion process is such that it providessuitable conditions for a fine grain recrystallized structure. Finegrain recrystallization is a primary objective of the inventive alloysdescribed herein. The fine grain crystallization yields a final aluminumproduct with superior yield strength and elongation properties.

Artificial aging of the extruded aluminum material at a particulartemperature for a particular time period provides suitable conditionsfor maximizing strength and elongation.

Chemistry and Casting

Aluminum alloys of the invention are high strength 6XXX alloys. In oneembodiment, aluminum alloys of the invention comprise mostly aluminumalong with at least about 1.05 weight percent silicon, at least about0.12 weight percent copper, about 0.20 weight percent manganese, and atleast 0.76 weight percent magnesium. Amounts of alloy components arestated in weight percent of alloy unless otherwise stated.

In one embodiment, aluminum alloys of the invention comprise from about0.90 percent to about 1.2 percent by weight silicon, up to about 0.5percent by weight iron, from about 0.05 percent to about 0.3 percent byweight copper, up to about 0.75 percent by weight manganese, from about0.70 percent to about 1.0 percent by weight magnesium, up to about 0.25percent by weight chromium, up to about 0.05 percent by weight zinc, upto about 0.1 percent by weight titanium, with the balance consistingessentially of aluminum.

In one embodiment, aluminum alloys of the invention comprise: about 1.13weight percent silicon, about 0.17 weight percent iron, about 0.16weight percent copper, about 0.21 weight percent manganese, about 0.80weight percent magnesium, about 0.004 weight percent chromium, about0.006 weight percent zinc, about 0.014 weight percent titanium, and thebalance consisting essentially of aluminum.

In one embodiment the total amount of impurities in the aluminum alloyis approximately zero. In one embodiment the total amount of impuritiesin the aluminum alloy comprise about 0.15 percent by weight. In oneembodiment the amount of any single impurity does not exceed about 0.05percent by weight.

Silicon may be present in the alloy in an amount between about 0.90percent to about 1.20 percent by weight. In one embodiment silicon ispresent in an amount between about 1.05 to about 1.12 percent by weight;in one embodiment silicon is present in an amount between about 1.05 toabout 1.10 percent by weight. Silicon may be present in the alloy in anamount of about 0.90, 0.91, 0.92, 0.93, 0.94, 0.95, 0.96, 0.97, 0.98,0.99, 1.00, 1.01, 1.02, 1.03, 1.04, 1.05, 1.06, 1.07, 1.08, 1.09, 1.10,1.11, 1.12, 1.13, 1.14, 1.15, 1.16, 1.17, 1.18, 1.19, or 1.20 percent byweight.

Iron may be present in the alloy in an amount up to about 0.50 percentby weight. In one embodiment iron is present in an amount up to about0.25 percent by weight. Iron may be present in the alloy in an amount ofabout zero, 0.01, 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.09, 0.10,0.11, 0.12, 0.13, 0.14, 0.15, 0.16, 0.17, 0.18, 0.19, 0.20, 0.21, 0.22,0.23, 0.24, 0.25, 0.26, 0.27, 0.28, 0.29, 0.30, 0.31, 0.32, 0.33, 0.34,0.35, 0.36, 0.37, 0.38, 0.39, 0.40, 0.41, 0.42, 0.43, 0.44, 0.45, 0.46,0.47, 0.48, 0.49, or 0.50 percent by weight.

Copper may be present in the alloy in an amount between about 0.05percent to about 0.3 percent by weight. In one embodiment copper ispresent in an amount between about 0.05 to about 0.30 percent by weight;in one embodiment copper is present in an amount between about 0.12 toabout 0.18 percent by weight; in one embodiment copper is present in anamount between about 0.09 to about 0.15 percent by weight. Copper may bepresent in the alloy in an amount of about 0.05, 0.06, 0.07, 0.08, 0.09,0.10, 0.11, 0.12, 0.13, 0.14, 0.15, 0.16, 0.17, 0.18, 0.19, 0.20, 0.21,0.22, 0.23, 0.24, 0.25, 0.26, 0.27, 0.28, 0.29, or 0.30 percent byweight.

Manganese may be present in the alloy in an amount up to about 0.75percent by weight. In one embodiment manganese is present in an amountbetween about 0.15 to about 0.75 percent by weight; in one embodimentmanganese is present in an amount between about 0.15 to about 0.20percent by weight; in one embodiment manganese is present in an amountbetween about 0.51 to about 0.56 percent by weight.

Manganese may be present in the alloy in an amount of about 0.01, 0.02,0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.09, 0.10, 0.11, 0.12, 0.13, 0.14,0.15, 0.16, 0.17, 0.18, 0.19, 0.20, 0.21, 0.22, 0.23, 0.24, 0.25, 0.26,0.27, 0.28, 0.29, 0.30, 0.31, 0.32, 0.33, 0.34, 0.35, 0.36, 0.37, 0.38,0.39, 0.40, 0.41, 0.42, 0.43, 0.44, 0.45, 0.46, 0.47, 0.48, 0.49, 0.50,0.51, 0.52, 0.53, 0.54, 0.55, 0.56, 0.57, 0.58, 0.59, 0.60, 0.61, 0.62,0.63, 0.64, 0.65, 0.66, 0.67, 0.68, 0.69, 0.70, 0.71, 0.72, 0.73, 0.74,or 0.75 percent by weight. While the amount of manganese present in thealloy may be below 0.10% or also zero, it is not preferred due to alowering of fracture toughness. Manganese adds resistance to therecrystallization process and to form a completely recrystallized grainstructure it is preferable that the manganese should be kept as close tozero as possible. Adding manganese, however, has positive effects on thefracture toughness of the material. Manganese is added to obtain finegrain recrystallization without negatively affecting the alloy'sfracture toughness.

Magnesium may be present in the alloy in an amount between about 0.70percent to about 1.0 percent by weight. In one embodiment magnesium ispresent in an amount between about 0.74 to about 0.80 percent by weight;in one embodiment magnesium is present in an amount between about 0.76to about 0.82 percent by weight. Magnesium may be present in the alloyin an amount of about 0.70, 0.71, 0.72, 0.73, 0.74, 0.75, 0.76, 0.77,0.78, 0.79, 0.80, 0.81, 0.82, 0.83, 0.84, 0.85, 0.86, 0.87, 0.88, 0.89,0.90, 0.91, 0.92, 0.93, 0.94, 0.95, 0.96, 0.97, 0.98, 0.99, or 1.0percent by weight.

Chromium adds resistance to the recrystallization process and to form acompletely recrystallized grain structure it is preferable that thechromium should be kept as close to zero as possible. Chromium may beabsent from the alloy (that is, zero percent by weight). Chromium may bepresent in the alloy in an amount up to about 0.250 percent by weight.In one embodiment chromium is present in an amount up to about 0.030percent by weight; in one embodiment chromium is present in an amount upto about 0.010 percent by weight; in one embodiment chromium is presentin an amount up to about 0.005 percent by weight. Chromium may bepresent in the alloy in an amount of about 0.005, 0.010, 0.015, 0.020,0.025, 0.030, 0.035, 0.040, 0.045, 0.050, 0.055, 0.060, 0.065, 0.070,0.075, 0.080, 0.085, 0.090, 0.095, 0.100, 0.105, 0.110, 0.115, 0.120,0.125, 0.130, 0.135, 0.140, 0.145, 0.150, 0.155, 0.160, 0.165, 0.170,0.175, 0.180, 0.185, 0.190, 0.195, 0.200, 0.205, 0.210, 0.215, 0.220,0.225, 0.230, 0.235, 0.240, 0.245, or 0.250 percent by weight. Chromiumis better at impeding recrystallization than manganese due to thedifferent locations at which the dispersoids form.

Zinc may be present in the alloy in an amount up to about 0.050 percentby weight. In one embodiment zinc is present in an amount up to about0.020 percent by weight; in one embodiment zinc is present in an amountup to about 0.005 percent by weight. Zinc may be present in the alloy inan amount of about zero, 0.005, 0.010, 0.015, 0.020, 0.025, 0.030,0.035, 0.040, 0.045, or percent by weight.

Titanium may be present in the alloy in an amount up to about 0.100percent by weight. In one embodiment titanium is present in an amount upto about 0.040 percent by weight; in one embodiment titanium is presentin an amount up to about 0.015 percent by weight. Titanium may bepresent in the alloy in an amount of about zero, 0.005, 0.010, 0.015,0.020, 0.025, 0.030, 0.035, 0.040, 0.045, 0.050, 0.055, 0.060, 0.065,0.070, 0.075, 0.080, 0.085, 0.090, 0.095, or 0.100 percent by weight.

Impurities may be present in the alloy in a total amount up to about0.150 percent by weight. Impurities may be present in the alloy in atotal amount of about zero, 0.005, 0.010, 0.015, 0.020, 0.025, 0.030,0.035, 0.040, 0.045, 0.050, 0.055, 0.060, 0.065, 0.110, 0.115, 0.120,0.125, 0.130, 0.135, 0.140, 0.145, or 0.150 percent by weight.

Amounts of each element included in the inventive aluminum alloy (thatis: silicon, iron, copper, manganese, magnesium, chromium, zinc,titanium, and impurities) may vary by between about 1% and about 25% ofthe desired value. Amounts of each element may vary by about 1%, 2%, 3%,4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%,19%, 20%, 21%, 22%, 23%, 24%, or 25% of the desired value. By way ofnon-limiting example, in an inventive alloy designed to comprise siliconat about 1.0 percent by weight where the amount of silicon may vary by10%, the final alloy may comprise silicon at between about 0.9 percentby weight to about 1.1 percent by weight. In another non-limitingexample, in an inventive alloy designed to comprise copper at about 0.15percent by weight where the amount of copper may vary by 20%, the finalalloy may comprise copper at between about 0.12 percent by weight toabout 0.18 percent by weight.

The alloy may be cast into logs or billets according to conventionalmethods. In particular, the alloy may be cast at a temperature aboveabout 1300° F., more particularly between about 1310° F. and about 1330°F. Logs may be cast into any appropriate size or shape as needed.

Directly after casting, the microstructure of the logs or billets maynot be uniform due to the solidification process. Solidification startswith the α-aluminum, by nature of the phase diagram. The aluminum formssingle crystal dendrites with respect to the direction of heat transferwhile the area surrounding the dendrites is solute rich with Mg₂Si whichneeds to be dissolved. In order to uniformly disperse the alloyingadditions throughout the α-aluminum matrix, the cast aluminum ishomogenized.

Homogenization may take place at a temperature below the castingtemperature, preferably at a temperature between about 1045° F. andabout 1070° F. The cast aluminum should be homogenized at an elevatedtemperature and for sufficient time to permit the alloying elementsenergy needed to diffuse into the aluminum dendrite arms to develop amore uniform microstructure. In one embodiment, homogenization occursover the span of several hours, in one embodiment homogenization occursover about four hours. Homogenization may occur in a furnace such as aCanefco furnace.

Extruding and Quenching

After casting the aluminum alloy into a log or billet, the aluminum isextruded through a press to obtain a desired shape or form. The billetmay be extruded through the press at any appropriate temperature basedon the size and shape of the extrusion. Initial billet temperatureshould be selected to ensure the material has the ability to extrudeeasily. The temperature is chosen for productivity and ensuring a finegrain recrystallized structure. Initial billet temperature may be belowthe homogenization temperature. In one embodiment the initial billettemperature is over about 800° F.; in one embodiment the initial billettemperature is between about 840° F. and about 880° F.; in oneembodiment the initial billet temperature is between about 850° F. andabout 870° F.; the initial billet temperature may be about 850° F.,about 855° F., about 860° F., about 865° F., or about 870° F.

The billet may be extruded through the press using a ram at anyappropriate speed based on the size and shape of the extrusion. In oneembodiment the press ram speed is between about 9.0 and about 13.0inches per minute; in one embodiment the press ram speed is betweenabout 9.0 and about 10.0 inches per minute; in one embodiment the pressram speed is between about 12.0 and about 12.5 inches per minute.

The aluminum material exits the extruder at an exit temperature greaterthan the initial billet temperature. In one embodiment the exittemperature of the aluminum material is about 1040° F. Highertemperatures are preferred over lower exit temperatures because lowerexit temperatures negatively affects the strength of the metal.

Following exit from the extrusion press, the aluminum material isquenched with water. The temperature is decreased from a temperature ofapproximately the exit temperature down to approximately ambienttemperature over the span of several seconds. In one embodiment thealuminum material is quenched in between about 8 to about 16 seconds; inone embodiment the aluminum material is quenched in between about 10 toabout 14 seconds; the aluminum material may be quenched in about 8seconds, about 9 seconds, about 10 seconds, about 11 seconds, about 12seconds, about 13 seconds, about 14 seconds, about 15 seconds, or about16 seconds.

Sections of the aluminum extrusion may have any suitable thickness, andthe preferred thickness of extrusion sections may range from about 0.050inch to about 0.500 inch. In one embodiment the thickness of each wallof an aluminum extrusion is between about 0.080 and about 0.200 inches;in one embodiment the thickness of each wall of an aluminum extrusion isbetween about 0.080 and about 0.150 inches.

Artificial Aging

After quenching, the extruded aluminum material may be placed in afurnace to stabilize it. Stabilization may occur at any appropriatefurnace temperature for any appropriate time; in one embodiment thefurnace temperature is about 250° F. and the aluminum is stabilized inthe furnace for about two hours.

To achieve full strength, the aluminum extrusion must be artificiallyaged by heating the aluminum material to an appropriate temperature foran appropriate time. Artificial aging temperatures may range from about300° F. to about 450° F.; in one embodiment the temperature ranges fromabout 320° F. to about 385° F.; in one embodiment the temperature rangesfrom about 320° F. to about 330° F.; in one embodiment the temperatureranges from about 335° F. to about 350° F.; in one embodiment thetemperature ranges from about 355° F. to about 365° F.; in oneembodiment the temperature ranges from about 370° F. to about 385° F.;the temperature may be about 300° F., about 305° F., about 310° F.,about 315° F., about 320° F., about 325° F., about 330° F., about 335°F., about 340° F., about 345° F., about 350° F., about 355° F., about360° F., about 365° F., about 370° F., about 375° F., about 380° F.,about 385° F., about 390° F., about 395° F., about 400° F., about 405°F., about 410° F., about 415° F., about 420° F., about 425° F., about430° F., about 435° F., about 440° F., about 445° F., or about 450° F.In a preferred embodiment the artificial aging temperature ranges fromabout 335° F. to about 350° F.

Artificial aging conditions may be applied for between about 1 to about16 hours; in one embodiment the artificial aging conditions are appliedfrom about 2 to about 12 hours; in one embodiment the artificial agingconditions are applied from about 2 to about 10 hours; in one embodimentthe artificial aging conditions are applied from about 4 to about 16hours; in one embodiment the artificial aging conditions are appliedfrom about 1 to about 6 hours; the artificial aging conditions may beapplied for about 1 hour, about 2 hours, about 3 hours, about 4 hours,about 5 hours, about 6 hours, about 7 hours, about 8 hours, about 9hours, about 10 hours, about 11 hours, about 12 hours, about 13 hours,about 14 hours, about 15 hours, or about 16 hours. In a preferredembodiment the artificial aging conditions are applied for about sixhours. In one preferred embodiment, the artificial aging temperatureranges from about 335° F. to about 350° F. and the conditions areapplied for about six hours.

Material Testing—Tensile Properties

Tensile strength may be measured manually or by an automated process.Automated tests may be performed, for example, on a Zwick AutomatedTensile Test Machine.

Ultimate tensile strength of the extruded and artificially aged aluminummaterial may be greater than about 310 MPa; in one embodiment theultimate tensile strength may range from about 310 MPa to about 370 MPa.The ultimate tensile strength may be about 310 MPa, about 315 MPa, about320 MPa, about 325 MPa, about 330 MPa, about 335 MPa, about 340 MPa,about 345 MPa, about 350 MPa, about 355 MPa, about 360 MPa, about 365MPa, or about 370 MPa. In comparison, the ultimate tensile strength ofan extruded and naturally aged inventive aluminum alloy may range fromabout 260 MPa to about 295 MPa. In a preferred embodiment the ultimatetensile strength of the extruded and artificially aged aluminum materialis greater than about 320 MPa; in a preferred embodiment the ultimatetensile strength of the extruded and artificially aged aluminum materialis between about 340 MPa and about 360 MPa; in a preferred embodimentthe ultimate tensile strength of the extruded and artificially agedaluminum material is about 350 MPa.

Yield strength of the extruded and artificially aged aluminum materialmay be greater than about 275 MPa; in one embodiment the ultimatetensile strength may range from about 285 MPa to about 350 MPa. Theultimate tensile strength may be about 285 MPa, about 290 MPa, about 295MPa, about 300 MPa, about 305 MPa, about 310 MPa, about 315 MPa, about320 MPa, about 325 MPa, about 330 MPa, about 335 MPa, about 340 MPa,about 345 MPa, or about 350 MPa. In comparison, the yield strength of anextruded and naturally aged inventive aluminum alloy may range fromabout 140 MPa to about 180 MPa. In a preferred embodiment the yieldstrength of the extruded and artificially aged aluminum material isgreater than about 320 MPa; in a preferred embodiment the yield strengthof the extruded and artificially aged aluminum material is between about325 MPa and about 335 MPa.

Elongation of the extruded and artificially aged aluminum material maybe less than about 17%; in one embodiment the elongation may range fromabout 17% to about 7.0%. The elongation may be about 17.0%, about 16.5%,about 16.0%, about 15.5%, about 15.0%, about 14.5%, about 14.0%, about13.5%, about 13.0%, about 12.5%, about 12.0%, about 11.5%, about 11.0%,about 10.5%, about 10.0%, about 9.5%, about 9.0%, about 8.5%, about8.0%, about 7.5%, or about 7.0%. In comparison, the elongation of anextruded and naturally aged inventive aluminum alloy may range fromabout 24.5% to about 21.0%. In a preferred embodiment the elongation ofthe extruded and artificially aged aluminum material is between about11.0% and about 14.0%.

Material Testing—Grain Structure and Die Structure

A primary objective of the new chemistry described herein is to achievefine grain recrystallization. Typically when a grain structure is fullyrecrystallized with fine grains, elongation properties are better, owingto the slip distances within the grains. The slip distance in smallergrains is significantly reduced when compared to larger grains. Sincegrains are randomly oriented in three dimensional space, the slip planeorientations are also along random directions.

When a single grain is under a tensile or compressive load, the slipplanes begin to experience a shearing stress. This stress will beginincreasing across the grain's slip system and separate the crystals.However, when considering a whole system of randomly oriented grains andslip planes, the matter becomes more complicated. The randomly orientedslip planes will be pulled in different directions causing the materialto elongate until one of the slip planes gives way and the piece breaks.With an increased number of grains and the shorter slip distance, thelocal stresses that develop due to grain boundary incompatibility arelower compared to material with larger grains.

To aid the alloy with fine grain recrystallization, the amount ofdispersoid elements, namely manganese and chromium, are adjusted. In oneembodiment, manganese is present in a range of about 0.15 to 0.2 andchromium is present at about 0.03 maximum. Both manganese and chromiumadd resistance to the recrystallization process, so to form a completelyrecrystallized grain structure, the elements would have been kept asclose to zero as possible. Adding manganese, however, has positiveeffects on the fracture toughness of the material. The manganese isadded in an effort to obtain fine grain recrystallization withoutnegatively affecting the fracture toughness.

In addition to alloy composition, the extrusion process impacts thealloy's recrystallization properties. Extruder die design may impact thegrain structure of the extruded aluminum material. Two aluminum billetsrun through two different dies at similar speeds and temperatures mayyield different grain structures based on die design. Specifically, thechoke and number of ports for aluminum to flow through may impact therecrystallization process.

A choke helps to east the aluminum metal through the due which, in turn,causes less strain energy to be present. The grains will notrecrystallize from the as-cast structure if there is not enough energyto do so. Presence of a choke will reduce the strain energy as the metalis pushed through the die and may result in unrecrystallized regions.Absence of choke will increase the strain energy as the metal is pushedthrough the die and which may result in recrystallized regions.

The number of ports may also impact the recrystallization process.Additional ports, or larger ports, may permit metal to flow through withgreater ease. The extruded aluminum will choose these paths of lowerresistance to flow. Increased metal flow will then increase the shearstresses in the metal, and increased shear stresses give the metal moreenergy to recrystallize

Initial billet temperature, extrusion speed, and exit temperatures alsoimpact the recrystallization process and, ultimately, the extrudedalloy's strength. Initial billet temperatures should be selected toensure the material may be extruded easily while achieving the desiredstrength and grain structure.

Conductivity of the extruded aluminum material, whether naturally orartificially aged, may be between about 40.0 and 50.0. The conductivitymay be about 40.0, about 41.0, about 42.0, about 43.0, about 44.0, about45.0, about 46.0, about 47.0, about 48.0, about 49.0, or about 50.0. Inone preferred embodiment the conductivity is between about 46.0 to about48.0; in one preferred embodiment the conductivity is about 46.0.

Having now fully described the subject alloys and methods it will beunderstood by those of ordinary skill in the art that the same can beperformed within equivalent ranges of conditions, formulations and otherparameters without affecting their scope or any embodiment thereof. Allcited patents, patent applications and publications are fullyincorporated by reference in their entirety.

The compositions and methods described herein will be better understoodwith reference to the following non-limiting examples.

Example 1 Casting

A new alloy designated HS6X was given the chemistry limits shown inTable 1.

TABLE 1 Target Chemistry for HS6X. Silicon Iron Copper ManganeseMagnesium Chromium Zinc Titanium (Si) (Fe) (Cu) (Mn) (Mg) (Cr) (Zn) (Ti)Minimum 1.05 — 0.12 0.15 0.76 — — —

Values are displayed in weight percents (balance aluminum).

HS6X was cast into 36 individual logs, each log was 10 inches indiameter and 140 inches long. The cast practice used is shown in Chart1.

The chemistry of HS6X was taken upon casting in three samples—A1, B1,and C1. Sample A1 was taken from the beginning of the cast, sample B2from the middle, and sample C1 from the end. This data is reported inTable 2.

TABLE 2 Chemistry of HS6X. Cast Sample Si Fe Cu Mn Mg Cr Zn Ti 3009102A1 1.12 0.17 0.16 0.21 0.79 0.004 0.006 0.015 B1 1.14 0.17 0.16 0.210.80 0.004 0.006 0.014 C1 1.15 0.17 0.16 0.21 0.81 0.004 0.006 0.014

Values are displayed in weight percents (balance aluminum).

Directly after casting, the microstructure of the logs was not uniformdue to the solidification process. In order to uniformly disperse thealloying additions throughout the α-aluminum matrix, the logs werehomogenized.

All of the logs were homogenized at 1045-1065° F. for four hours. Thiselevated temperature provides the alloying elements energy needed todiffuse into the aluminum dendrite arms to develop a more uniformmicrostructure.

Example 2 Extruding

Two automotive bumper sections were extruded with the HS6X alloy ofExample 1. The sections are shown in FIG. 1 and FIG. 2. Though thesections look similar, there are a few notable differences. Section569510 has a thinner wall when compared to section 569310. The centerand bottom walls of section 569510 also contain regions where the areais not consistent also known as reduced areas. Seven charges of eachsection were run and all charges were water quenched after leaving thepress. Reduced areas are indicated by arrows in FIG. 2.

Information about the billet temperature, ram speed, and exittemperature was gathered at the press during extrusion. The collecteddata is displayed in Table 3. Data for each charge was collected whenthe charge was halfway through completion near the middle of each chargeto insure that the speeds and temperatures were constant since breakoutspeeds and temperatures are lower than what the alloy is capable of.Charges one and two from both sections were determined to be notrepresentative of the whole because they ran slower and had a low exittemperature.

TABLE 3 Information gathered from press during extrusion process. PressRam Extrusion Speed Speed Billet (inches per (feet per Exit Temperatureminute - minute - Temperature Section Charge (° F.) IPM) FPM) (° F.)569310 1 852 9.1 42 1016 2 852 11.1 50 1020 3 853 12.2 56 1039 4 85012.1 56 1040 5 855 12.2 57 1038 6 859 12.3 57 1046 7 852 12.2 56 1040569510 1 864 4.9 30 1027 2 867 8.5 50 1034 3 867 9.0 55 1037 4 862 9.955 1041 5 867 10.0 59 1039 6 868 10.0 59 1040 7 865 9.9 56 1038

Water quench rate was found using a quench rate meter with twothermocouples attached to it. Quench rate graphs are displayed in FIG. 3for section 569310 and FIG. 4 for section 569510.

The quench rate data for the various charges is located at Table 4.

TABLE 4 Water Quench Rates for Various Charges Time Ambient TempThermocouple Section Charge (Seconds) (° C.) (° C.) 569310 3 2 30.2511.45 3 4 30.2 496.75 3 6 30.3 368.48 3 8 30.3 242.31 3 10 30.4 76.32 312 30.6 36.3 3 14 30.6 38.04 4 2 29.8 516.95 4 4 29.8 425.94 4 6 29.9357.25 4 8 29.9 211.07 4 10 30 49.4 4 12 30.2 38 5 2 30.3 518.54 5 430.3 442.5 5 6 30.3 356.22 5 8 30.4 218.19 5 10 30.6 44.9 5 12 30.737.45 569510 3 2 32.3 545.57 3 4 32.3 529.06 3 6 32.3 340.83 3 8 32.232.24 3 10 32.3 32.34 3 12 32.3 32.1 4 2 32.3 492.28 4 4 32.3 476.33 4 632.3 307.52 4 8 32.4 181.42 4 10 32.5 53.15 4 12 32.7 40.61 5 2 33.5485.14 5 4 33.6 322.61 5 6 33.6 251.84 5 8 33.6 224.34 5 10 33.6 202.165 12 33.6 60.89 6 2 34 527.33 6 4 34 516.22 6 6 34 417.73 6 8 34 265.086 10 34.2 51.31 6 12 34.4 40.96 6 14 34.5 39.84 7 2 34 512.24 7 4 34426.96 7 6 34 327.35 7 8 34.2 77.65 7 10 34.4 42.36 7 12 34.5 41.53 7 1434.6 42.1

Example 3 Natural Aging

Natural age testing was performed on section 569310 of Example 2 only.The time periods for this aging process were 0, 1, 2, 3, 5, 10, 15, 20,25, 30, 35, 40, 50, and 60 days. After each time period was completed,conductivity measurements and tensile tests were used to determinechanges in strength. Tensile test locations for section 569310 aredisplayed in FIG. 5 (indicated by ovals). Since the section of 569310 ismostly symmetrical, the extrusion was cut along the dashed line so thatboth sides could be utilized for testing.

Natural age conductivity and tensile data for section 569310 is reportedin Table 5. The ultimate tensile strength, yield strength, andelongation as a function of natural age time are displayed in FIG. 7,FIG. 8, and FIG. 9, respectively.

TABLE 5 Natural Age Tensile and Conductivity Data for Section 569310Con- Elon- Time Sample duc- Tensile Yield gation Period ID tivity ksimpa ksi mpa % Day 1-6T 37.3 257.18 19.5 134.45 25.0 0.5 1-6B 37.0 255.1219.1 131.69 23.0 (tested 2-1T 36.9 254.43 19.8 136.52 23.0 by 2-1B 36.9254.43 20.1 138.59 23.0 hand) 3-8T 38.2 263.39 19.9 137.21 24.0 3-8B37.4 257.87 19.4 133.76 20.0 4-4T 37.7 259.94 19.2 132.38 22.5 4-4B 37.6259.25 20.6 142.04 22.5 6-7T 39.4 271.66 21.9 151.00 24.5 6-7B 38.5265.46 21.1 145.48 21.5 7-4T 39.2 270.28 20.8 143.42 22.0 7-4B 38.6266.15 22.1 152.38 21.5 Day 1-6T 38.42 264.91 21.09 145.42 23.25 1 1-6B37.51 258.63 20.23 139.49 22.33 2-1T 37.89 261.25 21.02 144.93 23.872-1B 37.82 260.77 20.82 143.55 21.37 3-8T 39.13 269.80 21.69 149.5522.79 3-8B 38.60 266.15 22.00 151.69 21.80 4-4T 37.79 260.56 21.01144.86 20.97 4-4B 38.70 266.84 20.80 143.42 21.50 6-7T 40.05 276.1423.12 159.41 21.75 6-7B 38.58 266.01 22.52 155.28 21.89 7-4T 40.15276.83 23.45 161.69 22.39 7-4B 38.60 266.15 22.71 156.59 22.81 Day 1-6T42.9 38.69 266.77 20.88 143.97 22.71 2 1-6B 38.80 267.53 21.33 147.0721.96 2-1T 42.8 38.44 265.04 21.38 147.42 23.41 2-1B 39.10 269.59 21.93151.21 22.79 3-8T 42.3 39.31 271.04 21.50 148.24 23.01 3-8B 38.94 268.4921.66 149.35 20.68 4-4T 42.6 39.33 271.18 22.38 154.31 22.61 4-4B 38.94268.49 22.36 154.17 21.29 6-7T 41.8 40.35 278.21 23.23 160.17 23.17 6-7B39.51 272.42 23.19 159.90 20.66 7-4T 41.7 40.47 279.04 23.62 162.8621.89 7-4B 39.68 273.59 23.54 162.31 20.53 Day 1-6T 43.0 39.44 271.9422.08 152.24 22.85 3 1-6B 38.71 266.91 21.43 147.76 23.33 2-1T 42.939.00 268.91 22.02 151.83 23.65 2-1B 38.65 266.49 21.81 150.38 21.613-8T 42.4 40.30 277.87 22.63 156.03 23.30 3-8B 38.70 266.84 21.92 151.1420.14 4-4T 42.6 39.34 271.25 23.01 158.65 23.46 4-4B 38.84 267.80 22.11152.45 19.48 6-7T 41.8 41.19 284.01 23.96 165.20 22.44 6-7B 39.17 270.0823.17 159.76 21.20 7-4T 41.7 41.17 283.87 24.34 167.82 21.83 7-4B 39.21270.35 23.57 162.52 19.93 Day 1-6T 40.31 277.94 22.60 155.83 22.10 51-6B 39.35 271.32 21.91 151.07 21.49 2-1T 39.73 273.94 22.75 156.8623.10 2-1B 39.27 270.77 22.36 154.17 21.57 3-8T 41.08 283.25 23.89164.72 21.93 3-8B 39.42 271.80 22.84 157.48 21.96 4-4T 40.87 281.8023.62 162.86 21.57 4-4B 39.94 275.39 22.98 158.45 20.25 6-7T 41.86288.62 24.59 169.55 22.53 6-7B 40.02 275.94 23.88 164.65 20.12 7-4T41.93 289.11 24.89 171.62 22.32 7-4B 40.16 276.90 24.16 166.58 20.80 Day1-6T 43.0 40.18 277.04 22.29 153.69 23.02 10 1-6B 39.96 275.52 22.63156.03 22.11 2-1T 42.7 39.77 274.21 22.63 156.03 23.59 2-1B 39.86 274.8323.00 158.59 21.58 3-8T 42.1 41.05 283.04 23.60 162.72 22.21 3-8B 40.63280.14 23.53 162.24 20.68 4-4T 42.2 41.04 282.97 23.63 162.93 21.79 4-4B40.81 281.38 23.68 163.27 21.55 6-7T 41.6 41.81 288.28 24.54 169.2021.32 6-7B 41.29 284.69 24.47 168.72 21.11 7-4T 41.6 41.86 288.62 24.91171.75 21.61 7-4B 41.33 284.97 24.82 171.13 21.73 Day 1-6T 42.9 41.5286.14 23.8 164.10 23.5 15 1-6B 40.5 279.25 20.0 137.90 22.5 (tested2-1T 42.8 40.9 282.01 23.9 164.79 25.0 by 2-1B 40.7 280.63 23.5 162.0323.0 hand) 3-8T 42.2 42.1 290.28 25.0 172.38 23.0 3-8B 40.5 279.25 23.8164.10 21.5 4-4T 42.3 42.1 290.28 24.6 169.62 24.0 4-4B 41.5 286.14 23.7163.41 23.0 6-7T 41.6 43.0 296.49 24.7 170.31 24.0 6-7B 41.4 285.45 24.9171.69 22.0 7-4T 41.6 42.8 295.11 25.6 176.51 23.5 7-4B 41.1 283.38 23.9164.79 22.0 Day 1-6T 42.7 40.9 282.01 22.6 155.83 24.0 20 1-6B 40.6279.94 22.5 155.14 24.5 (tested 2-1T 42.5 40.7 280.63 23.1 159.27 24.5by 2-1B 40.6 279.94 23.2 159.96 23.0 hand) 3-8T 42.0 41.7 287.52 23.8164.10 23.0 3-8B 41.1 283.38 23.4 161.34 22.5 4-4T 42.2 41.8 288.21 24.2166.86 22.5 4-4B 41.4 285.45 24.3 167.55 22.5 6-7T 41.6 42.5 293.04 24.6169.62 25.0 6-7B 41.7 287.52 24.9 171.69 23.0 7-4T 41.5 42.7 294.42 25.4175.13 23.0 7-4B 42.0 289.59 25.4 175.13 22.0 Day 1-6T 42.7 41.27 284.5623.58 162.58 23.99 25 1-6B 40.50 279.25 22.67 156.31 24.64 2-1T 42.840.71 280.70 23.68 163.27 25.15 2-1B 40.45 278.90 23.51 162.10 22.583-8T 42.3 42.01 289.66 24.65 169.96 22.36 3-8B 40.47 279.04 23.77 163.8921.22 4-4T 42.3 41.69 287.45 24.56 169.34 24.61 4-4B 40.92 282.14 23.95165.14 22.34 6-7T 41.4 43.01 296.55 25.64 176.79 22.72 6-7B 40.75 280.9724.64 169.89 21.07 7-4T 41.9 42.94 296.07 25.88 178.44 22.30 7-4B 40.81281.38 25.00 172.38 19.89 Day 1-6T 42.5 40.85 281.66 22.9 157.90 23.8130 1-6B 40.62 280.07 23.05 158.93 24.74 2-1T 42.3 40.57 279.73 23.28160.52 25.51 2-1B 40.67 280.42 23.52 162.17 24.73 3-8T 41.6 41.68 287.3824.07 165.96 25.38 3-8B 41.24 284.35 23.95 165.14 23.69 4-4T 42.1 41.51286.21 24.22 167.00 24.09 4-4B 41.39 285.38 24.18 166.72 24.37 6-7T 41.242.45 292.69 25.18 173.62 24.44 6-7B 41.9 288.90 24.4 168.24 22.28 7-4T41.3 42.35 292.00 25.37 174.93 23.92 7-4B 41.84 288.49 25.28 174.3123.26 Day 1-6T 42.6 41.26 284.49 23.58 162.58 25.5 35 1-6B 40.5 279.2522.95 158.24 26.11 2-1T 42.7 40.65 280.28 23.67 163.20 26.14 2-1B 40.48279.11 23.44 161.62 24.51 3-8T 41.8 42.04 289.87 24.8 171.00 23.98 3-8B40.58 279.80 24 165.48 22 4-4T 42.1 41.75 287.87 24.59 169.55 25.73 4-4B40.88 281.87 24.1 166.17 20.8 6-7T 41.3 42.98 296.35 25.67 176.99 26.426-7B 40.94 282.28 24.72 170.44 23.15 7-4T 41.6 42.82 295.24 25.87 178.3723.61 7-4B 41.11 283.45 25.07 172.86 22.7 Day 1-6T 41.4 285.45 22.94158.17 26 40 1-6B 40.93 282.21 22.34 154.03 24 (tested 2-1T 40.8 281.3221.4 147.55 25 by 2-1B 40.8 281.32 23.6 162.72 24 hand) 3-8T 42 289.5924.2 166.86 24 3-8B 42 289.59 23.6 162.72 23 4-4T 42 289.59 24.6 169.6224 4-4B 41.5 286.14 23.8 164.10 23 6-7T 42.8 295.11 24.9 171.69 25 6-7B42.3 291.66 24.2 166.86 22 7-4T 43 296.49 23.5 162.03 24 7-4B 41.9288.90 24.7 170.31 23 Day 1-6T 41.61 286.90 24.21 166.93 24.65 50 1-6B40.79 281.25 23.21 160.03 23.02 2-1T 41.16 283.80 24.04 165.76 24.072-1B 40.84 281.59 24.33 167.76 21.71 3-8T 42.54 293.31 28.21 194.5121.26 3-8B 41.05 283.04 23.91 164.86 21.54 4-4T 41.88 288.76 24.79170.93 22.93 4-4B 41.28 284.63 24.76 170.72 20.5 6-7T 43.34 298.83 26.02179.41 23.59 6-7B 41.4 285.45 25.43 175.34 21.16 7-4T 43.4 299.24 26.31181.41 22.68 7-4B 41.62 286.97 25.69 177.13 21.52 Day 1-6T 42.4 0.000.00 60 1-6B 0.00 0.00 2-1T 42.4 0.00 0.00 2-1B 0.00 0.00 3-8T 41.7 0.000.00 3-8B 0.00 0.00 4-4T 42.0 0.00 0.00 4-4B 0.00 0.00 6-7T 41.2 0.000.00 6-7B 0.00 0.00 7-4T 41.3 0.00 0.00 7-4B 0.00 0.00

Example 4 Artificial Aging

The aluminum of Example 2 that was not used for natural age testing inExample 3 was placed in a furnace at 250° F. for two hours in order tostabilize it. Stabilizing the metal prevented the loss of artificialaging response (e.g. strength loss) that occurs in 6XXX alloys when theyhave significant natural aging time. The stabilized pieces could then beused for artificial age testing independent of the effect of varyingnatural aging times on strength.

Unlike the natural age testing in Example 3, both extruded sections569310 and 569510 of Example 2 were aged and tested. Tensile testlocations for section 569510 are shown in FIG. 6 (indicated by ovals).Since the section of 569510 had reduced areas indicated by arrows alongthe bottom of one side, both sides could not be used for testingpurposes.

Several artificial aging conditions were used to determine the newalloy's aging kinetics and properties. Table 6 lists the conditions usedfor the aging process. After the metal was aged, conductivitymeasurements and tensile tests were used to determine the strength ofthe material.

TABLE 6 Aging conditions used for artificial age testing Temperature (°F.) Time (Hours) 320/329 4 8 12 16 338/347 2 4 6 8 10 12 356/365 2 4 6 810 374/383 1 2 3 4 5 6

Artificial age conductivity and tensile data for section 569310 isreported in Table 7. The ultimate tensile strength, yield strength, andelongation as a function of age time and temperature for section 569310are displayed in FIGS. 10-12.

TABLE 7 Artificial Age Tensile and Conductivity Data for Section 569310Temp Age Conduc- Tensile Yield Elongation (° F.) Time Piece tivity ksimpa ksi mpa % Stabilized 1-8-4T 43.3 40.95 282.35 23.57 162.52 23.161-8-4B 40.37 278.35 23.13 159.48 22.78 2-6-4T 42.9 41.19 284.01 23.86164.51 22.27 2-6-4B 40.81 281.38 23.44 161.62 22.12 3-1-3T 43.1 40.39278.49 23.12 159.41 23.20 3-1-3B 39.88 274.97 22.66 156.24 21.33 4-7-4T42.5 42.02 289.73 24.38 168.10 20.36 4-7-4B 40.60 279.94 23.42 161.4822.41 5-4-2T 42.5 41.37 285.25 24.17 166.65 21.44 5-4-2B 40.04 276.0823.20 159.96 20.18 6-4-3T 42.2 42.39 292.28 25.09 173.00 20.90 6-4-3B40.67 280.42 24.22 167.00 19.90 7-7-2T 41.8 42.66 294.14 25.53 176.0322.82 7-7-2B 40.81 281.38 24.78 170.86 19.75 320/329 4 1-8-3T 45.2 49.60341.99 42.00 289.59 18.00 (Tested 4 1-8-3B 48.90 337.17 41.30 284.7618.00 by Hand) 4 2-8-3T 44.4 50.00 344.75 41.00 282.70 19.00 4 2-8-3B49.00 337.86 41.20 284.07 18.00 4 3-6-3T 44.3 50.00 344.75 42.30 291.6617.00 4 3-6-3B 49.00 337.86 40.90 282.01 16.00 4 5-7-3T 44.0 50.80350.27 42.40 292.35 17.00 4 5-7-3B 48.90 337.17 41.60 286.83 17.00 47-7-5T 43.6 50.60 348.89 43.60 300.62 16.00 4 7-7-5B 49.20 339.23 41.80288.21 16.00 8 2-6-2T 46.1 51.70 356.47 47.20 325.44 15.50 8 2-6-2B50.90 350.96 46.60 321.31 16.00 8 3-1-1T 46.2 51.40 354.40 46.20 318.5516.00 8 3-1-1B 50.80 350.27 45.20 311.65 15.00 8 4-7-3T 45.5 52.20359.92 47.10 324.75 15.00 8 4-7-3B 51.30 353.71 46.70 322.00 15.00 85-4-1T 45.6 51.90 357.85 46.70 322.00 15.00 8 5-4-1B 51.00 351.65 45.40313.03 15.00 8 6-4-1T 45.0 52.40 361.30 45.00 310.28 15.00 8 6-4-1B51.40 354.40 41.10 283.38 15.00 8 7-7-4T 44.7 51.80 357.16 47.60 328.2014.50 8 7-7-4B 51.30 353.71 47.70 328.89 14.00 12 1-8-3T 47.6 51.50355.09 48.00 330.96 14.00 12 1-8-3B 51.20 353.02 46.80 322.69 14.00 122-6-4T 46.8 52.20 359.92 48.60 335.10 15.00 12 2-6-4B 51.60 355.78 39.40271.66 15.00 12 3-1-5T 47.1 51.40 354.40 48.20 332.34 16.00 12 3-1-5B51.40 354.40 46.20 318.55 14.50 12 4-7-4T 46.1 52.40 361.30 49.00 337.8614.00 12 4-7-4B 51.40 354.40 48.10 331.65 14.50 12 5-4-4T 46.2 52.40361.30 48.70 335.79 15.00 12 5-4-4B 51.30 353.71 46.20 318.55 14.00 126-4-5T 45.8 52.80 364.06 47.80 329.58 15.00 12 6-4-5B 51.50 355.09 48.70335.79 14.00 16 2-6-5T 47.4 52.40 361.30 49.20 339.23 14.00 16 2-6-5B51.60 355.78 47.90 330.27 13.00 16 3-1-2T 47.5 51.70 356.47 48.70 335.7914.00 16 3-1-2B 51.10 352.33 48.30 333.03 14.00 16 4-7-1T 46.6 52.80364.06 49.90 344.06 13.00 16 4-7-1B 51.80 357.16 48.60 335.10 13.00 165-4-1T 46.7 52.30 360.61 49.50 341.30 13.00 16 5-4-1B 51.30 353.71 45.80315.79 12.50 16 6-4-2T 46.3 53.10 366.12 50.60 348.89 12.00 16 6-4-2B51.90 357.85 49.60 341.99 12.00 16 7-7-3T 46.1 53.00 365.44 51.00 351.6512.00 16 7-7-3B 51.90 357.85 49.50 341.30 12.00 338/347 2 1-8-2T 45.548.79 336.41 42.61 293.80 14.34 (30-44, 2 1-8-2B 48.85 336.82 42.53293.24 15.10 46 tested 2 2-8-3T 44.6 49.75 343.03 43.49 299.86 13.82 byhand) 2 2-8-3B 49.61 342.06 43.42 299.38 12.99 2 3-6-3T 44.5 49.82343.51 43.27 298.35 13.43 2 3-3-6B 49.75 343.03 43.46 299.66 12.96 25-7-3T 44.4 50.44 347.78 44.65 307.86 13.08 2 5-7-3B 50.12 345.58 44.42306.28 11.34 2 7-7-1T 44.1 50.99 351.58 45.50 313.72 12.99 2 7-7-1B50.53 348.40 45.21 311.72 12.85 4 2-6-4T 46.3 50.97 351.44 46.94 323.6511.84 4 2-6-4B 50.83 350.47 46.84 322.96 11.80 4 3-1-2T 46.7 50.28346.68 46.43 320.13 11.17 4 3-1-2B 50.54 348.47 46.55 320.96 12.13 44-7-2T 45.8 51.41 354.47 47.53 327.72 11.06 4 4-7-2B 51.53 355.30 47.67328.68 10.32 4 5-4-3T 45.9 51.22 353.16 47.36 326.55 10.63 4 5-4-3B51.34 353.99 47.58 328.06 11.21 4 6-4-4T 45.7 51.77 356.95 48.28 332.8910.40 4 6-4-4B 51.70 356.47 48.36 333.44 10.29 4 7-7-3T 45.4 51.99358.47 48.44 333.99 10.51 4 7-7-3B 51.73 356.68 48.55 334.75 10.42 61-8-3T 47.3 50.26 346.54 46.94 323.65 11.33 6 1-8-3B 50.29 346.75 47.07324.55 11.41 6 2-6-1T 46.8 50.89 350.89 47.55 327.86 11.03 6 2-6-1B50.87 350.75 47.53 327.72 11.13 6 3-1-5T 47.0 50.55 348.54 47.37 326.6211.94 6 3-1-5B 50.46 347.92 47.17 325.24 11.23 6 4-7-5T 46.4 51.79357.09 48.45 334.06 10.32 6 4-7-5B 51.80 357.16 48.40 333.72 14.00 65-4-5T 46.4 51.80 357.16 48.40 333.72 13.00 6 5-4-5B 51.80 357.16 48.80336.48 12.00 6 6-4-2T 46.1 52.30 360.61 44.20 304.76 12.00 6 6-4-2B52.20 359.92 49.50 341.30 11.00 8 2-6-3T 47.2 51.40 354.40 48.50 334.4111.00 8 2-6-3B 51.10 352.33 48.00 330.96 11.00 8 3-1-3T 47.4 50.40347.51 47.40 326.82 13.00 8 3-1-3B 50.70 349.58 47.40 326.82 12.00 84-7-3T 46.9 52.00 358.54 48.70 335.79 12.00 8 4-7-3B 51.70 356.47 48.90337.17 12.00 8 5-4-2T 46.8 51.50 355.09 46.30 319.24 12.00 8 5-4-2B51.80 357.16 47.80 329.58 11.50 8 6-4-1T 46.6 52.30 360.61 49.70 342.6811.00 8 6-4-1B 52.30 360.61 49.90 344.06 11.50 8 7-7-4T 46.5 52.29360.54 49.91 344.13 8.87 8 7-7-4B 52.20 359.92 49.30 339.92 10.50 101-8-2T 48.1 50.02 344.89 47.32 326.27 11.95 10 1-8-2B 50.05 345.09 47.19325.38 10.24 10 2-6-1T 48.0 50.42 347.65 47.64 328.48 11.12 10 2-6-1B50.59 348.82 47.63 328.41 10.69 10 3-1-2T 47.9 49.97 344.54 47.01 324.1311.70 10 3-1-2B 50.06 345.16 46.87 323.17 11.36 10 4-7-1T 47.6 51.48354.95 48.66 335.51 8.89 10 4-7-1B 50.96 351.37 48.08 331.51 9.49 105-4-5T 47.5 51.20 353.02 48.36 333.44 10.03 10 5-4-5B 50.72 349.71 47.83329.79 9.91 10 6-4-1T 46.9 51.72 356.61 49.27 339.72 8.24 10 6-4-1B51.06 352.06 48.06 331.37 8.99 10 7-7-2T 46.9 52.11 359.30 49.92 344.209.54 10 7-7-2B 51.19 352.96 49.37 340.41 8.82 12 1-8-1T 48.5 49.72342.82 47.03 324.27 11.23 12 1-8-1B 49.60 341.99 46.83 322.89 10.63 122-6-1T 48.1 49.99 344.68 47.28 326.00 11.28 12 2-6-1B 50.12 345.58 47.29326.06 10.26 12 3-1-1T 47.9 49.58 341.85 46.70 322.00 12.29 12 3-1-1B49.58 341.85 46.43 320.13 9.87 12 4-7-2T 47.4 51.07 352.13 48.50 334.418.68 12 4-7-2B 50.61 348.96 47.89 330.20 8.91 12 5-4-5T 47.2 50.75349.92 48.07 331.44 10.07 12 5-4-5B 50.32 346.96 47.57 328.00 10.32 126-4-4T 47.2 51.48 354.95 49.07 338.34 8.73 12 6-4-4B 50.79 350.20 48.46334.13 8.77 12 7-7-5T 47.0 51.75 356.82 49.63 342.20 7.79 12 7-7-5B50.83 350.47 49.11 338.61 7.79 356/365 2 2-6-5T 46.7 50.66 349.30 47.18325.31 12.18 2 2-6-5B 50.47 347.99 46.70 322.00 11.10 2 3-1-4T 46.750.09 345.37 46.36 319.65 13.05 2 3-1-4B 49.92 344.20 46.02 317.31 11.002 4-7-5T 46.2 51.62 355.92 48.16 332.06 9.98 2 4-7-5B 50.66 349.30 46.63321.51 11.03 2 5-4-3T 46.1 51.09 352.27 47.54 327.79 11.20 2 5-4-3B50.49 348.13 46.74 322.27 10.97 2 6-4-2T 45.9 51.95 358.20 48.74 336.0610.03 2 6-4-2B 50.79 350.20 47.84 329.86 10.12 2 7-7-3T 45.6 52.07359.02 48.95 337.51 9.56 2 7-7-3B 50.92 351.09 48.07 331.44 11.51 41-8-4T 48.1 50.02 344.89 47.20 325.44 11.21 4 1-8-4B 49.89 343.99 46.98323.93 10.82 4 2-6-3T 47.6 50.38 347.37 47.63 328.41 10.75 4 2-6-3B50.42 347.65 47.42 326.96 10.56 4 3-1-4T 47.6 50.06 345.16 47.09 324.6911.35 4 3-1-4B 49.88 343.92 46.89 323.31 10.30 4 4-7-5T 47.0 51.58355.64 48.83 336.68 9.38 4 4-7-5B 50.80 350.27 47.95 330.62 8.79 45-4-4T 47.1 51.19 352.96 48.38 333.58 11.13 4 5-4-4B 50.48 348.06 47.11324.82 9.59 4 6-4-3T 46.7 51.94 358.13 49.43 340.82 9.31 4 6-4-3B 50.93351.16 48.51 334.48 9.46 4 7-7-4T 46.6 52.15 359.57 49.94 344.34 7.63 47-7-4B 51.11 352.40 49.47 341.10 8.26 6 1-8-2T 48.3 49.59 341.92 46.96323.79 10.83 6 1-8-2B 49.35 340.27 46.68 321.86 10.03 6 2-6-2T 48.049.77 343.16 47.16 325.17 10.30 6 2-6-2B 49.67 342.47 46.63 321.51 9.696 3-1-5T 47.9 49.26 339.65 46.48 320.48 11.19 6 3-1-5B 49.17 339.0346.16 318.27 10.24 6 4-7-3T 47.5 50.82 350.40 48.27 332.82 8.91 6 4-7-3B50.09 345.37 47.39 326.75 9.73 6 5-4-3T 47.5 50.43 347.71 47.80 329.589.08 6 5-4-3B 49.83 343.58 47.35 326.48 8.65 6 6-4-5T 47.2 51.22 353.1648.92 337.30 8.33 6 6-4-5B 49.94 344.34 48.32 333.17 9.60 6 7-7-1T 47.151.51 355.16 49.40 340.61 7.76 6 7-7-1B 50.65 349.23 48.95 337.51 9.02 81-8-1T 48.0 48.84 336.75 46.08 317.72 9.94 8 1-8-1B 48.64 335.37 45.83316.00 9.80 8 2-6-3T 48.3 48.93 337.37 46.23 318.76 10.42 8 2-6-3B 48.94337.44 46.25 318.89 9.13 8 3-1-3T 48.2 48.66 335.51 45.80 315.79 11.70 83-1-3B 48.49 334.34 45.43 313.24 9.73 8 4-7-2T 47.8 50.19 346.06 47.54327.79 9.17 8 4-7-2B 49.48 341.16 46.73 322.20 9.10 8 5-4-2T 47.7 49.60341.99 46.96 323.79 9.66 8 5-4-2B 49.13 338.75 46.35 319.58 8.99 86-4-4T 47.6 50.39 347.44 47.98 330.82 8.80 8 6-4-4B 49.56 341.72 47.30326.13 8.95 8 7-7-1T 47.4 50.90 350.96 48.69 335.72 8.57 8 7-7-1B 49.98344.61 48.01 331.03 7.80 10 1-8-3T 49.0 47.50 327.51 44.64 307.79 10.0110 1-8-3B 47.60 328.20 44.77 308.69 9.56 10 2-6-5T 48.3 48.22 332.4845.37 312.83 9.41 10 2-6-5B 48.17 332.13 45.35 312.69 10.04 10 3-1-4T48.1 47.46 327.24 44.43 306.34 10.84 10 3-1-4B 47.75 329.24 44.73 308.4110.00 10 4-7-3T 48.0 48.81 336.54 45.97 316.96 8.91 10 4-7-3B 48.88337.03 46.12 318.00 8.56 10 5-4-4T 47.9 48.55 334.75 45.68 314.96 9.1810 5-4-4B 48.54 334.68 45.76 315.52 10.37 10 6-4-3T 47.8 48.95 337.5146.46 320.34 9.59 10 6-4-3B 49.13 338.75 46.79 322.62 9.15 10 7-7-5T47.8 49.38 340.48 47.07 324.55 8.66 10 7-7-5B 49.53 341.51 47.65 328.557.80 374/383 1 2-6-1T 46.4 50.08 345.30 46.75 322.34 11.31 1 2-6-1B49.73 342.89 46.46 320.34 11.12 1 3-1-1T 46.9 49.27 339.72 45.86 316.2011.66 1 3-1-1B 49.30 339.92 45.86 316.20 10.29 1 5-4-1T 46.3 50.32346.96 46.85 323.03 10.71 1 5-4-1B 50.14 345.72 46.75 322.34 10.79 14-7-2T 46.2 50.59 348.82 47.17 325.24 10.33 1 4-7-2B 50.55 348.54 46.66321.72 10.55 1 6-4-5T 46.3 51.00 351.65 48.42 333.86 9.80 1 6-4-5B 50.73349.78 48.32 333.17 9.61 1 7-7-1T 46.3 51.48 354.95 48.85 336.82 9.57 17-7-1B 51.02 351.78 48.74 336.06 8.86 2 1-8-1T 47.8 49.14 338.82 46.24318.82 11.32 2 1-8-1B 48.97 337.65 46.18 318.41 11.04 2 2-6-2T 47.349.87 343.85 47.07 324.55 10.44 2 2-6-2B 49.41 340.68 47.10 324.75 10.382 3-1-1T 47.3 49.19 339.17 46.46 320.34 10.77 2 3-1-1B 49.15 338.8946.28 319.10 10.28 2 4-7-1T 47.0 50.60 348.89 47.73 329.10 8.99 2 4-7-1B50.40 347.51 47.73 329.10 9.15 2 5-4-4T 47.1 50.20 346.13 47.39 326.759.48 2 5-4-4B 50.13 345.65 47.36 326.55 10.50 2 6-4-2T 46.9 50.69 349.5148.26 332.75 9.33 2 6-4-2B 50.50 348.20 48.34 333.30 9.29 2 7-7-5T 46.851.08 352.20 48.91 337.23 9.18 2 7-7-5B 50.72 349.71 48.99 337.79 8.78 31-8-4T 48.3 48.67 335.58 46.02 317.31 10.69 3 1-8-4B 48.52 334.55 45.70315.10 9.98 3 2-6-5T 47.5 49.48 341.16 46.76 322.41 9.73 3 2-6-5B 49.23339.44 46.53 320.82 9.99 3 3-1-2T 47.5 48.64 335.37 45.77 315.58 10.39 33-1-2B 48.68 335.65 45.63 314.62 9.93 3 4-7-4T 47.4 50.06 345.16 47.59328.13 9.09 3 4-7-4B 50.00 344.75 47.38 326.69 9.63 3 5-4-2T 47.3 49.63342.20 46.92 323.51 9.55 3 5-4-2B 49.66 342.41 46.98 323.93 10.41 36-4-1T 47.3 50.08 345.30 47.60 328.20 9.06 3 6-4-1B 49.92 344.20 47.85329.93 9.83 3 7-7-2T 47.0 50.43 347.71 48.24 332.61 9.52 3 7-7-2B 50.10345.44 48.36 333.44 8.39 4 1-8-1T 48.6 47.88 330.13 45.01 310.34 10.87 41-8-1B 47.87 330.06 45.06 310.69 10.04 4 2-6-3T 47.9 48.69 335.72 45.85316.14 9.34 4 2-6-3B 48.48 334.27 45.65 314.76 9.13 4 3-1-5T 47.7 47.98330.82 45.05 310.62 10.08 4 3-1-5B 48.14 331.93 45.28 312.21 10.14 44-7-1T 47.6 49.48 341.16 46.90 323.38 8.69 4 4-7-1B 49.41 340.68 46.72322.13 9.38 4 5-4-5T 47.5 49.17 339.03 46.34 319.51 10.09 4 5-4-5B 49.02337.99 46.34 319.51 9.27 4 6-4-3T 47.4 49.43 340.82 46.57 321.10 9.13 46-4-3B 49.33 340.13 47.07 324.55 9.07 4 7-7-2T 47.3 49.81 343.44 47.60328.20 9.00 4 7-7-2B 49.60 341.99 47.78 329.44 8.19 5 1-8-2T 48.8 47.22325.58 44.29 305.38 10.52 5 1-8-2B 47.14 325.03 44.31 305.52 10.32 52-6-2T 48.1 47.78 329.44 44.80 308.90 9.65 5 2-6-2B 47.53 327.72 44.63307.72 10.16 5 3-1-3T 48.1 47.27 325.93 44.15 304.41 10.36 5 3-1-3B47.18 325.31 44.07 303.86 10.33 5 4-7-5T 47.9 48.74 336.06 45.83 316.009.15 5 4-7-5B 48.63 335.30 45.84 316.07 9.26 5 5-4-1T 47.8 48.09 331.5845.15 311.31 9.46 5 5-4-1B 47.88 330.13 44.91 309.65 9.63 5 6-4-4T 47.748.44 333.99 45.75 315.45 9.67 5 6-4-4B 48.27 332.82 45.82 315.93 10.025 7-7-4T 47.7 48.81 336.54 46.35 319.58 8.53 5 7-7-4B 48.60 335.10 46.61321.38 8.25 6 1-8-4T 49.0 45.85 316.14 42.62 293.86 10.98 6 1-8-4B 45.70315.10 42.66 294.14 9.66 6 2-6-4T 48.4 46.69 321.93 43.49 299.86 9.87 62-6-4B 46.40 319.93 43.30 298.55 9.48 6 3-1-4T 48.2 45.76 315.52 42.38292.21 10.71 6 3-1-4B 45.90 316.48 42.70 294.42 9.82 6 4-7-4T 48.0 47.06324.48 43.80 302.00 8.80 6 4-7-4B 47.23 325.65 44.35 305.79 9.37 65-4-3T 48.0 46.90 323.38 43.67 301.10 10.10 6 5-4-3B 46.93 323.58 43.84302.28 9.10 6 6-4-5T 47.8 47.52 327.65 44.58 307.38 9.70 6 6-4-5B 47.35326.48 44.72 308.34 8.97 6 7-7-3T 47.7 47.88 330.13 45.14 311.24 9.01 67-7-3B 47.49 327.44 45.08 310.83 9.25

Artificial age conductivity and tensile data for section 56951 isreported in Table 8. The ultimate tensile strength, yield strength, andelongation as a function of age time and temperature for section 569510are displayed in FIG. 13, FIG. 14, and FIG. 15, respectively.

TABLE 8 Artificial Age Tensile and Conductivity Data for Section 569510Con- Elon- Temp Age duc- Tensile Yield gation (° F.) Time Piece tivityksi mpa ksi mpa % Stabi- 1-5-5T 42.6 39 268.9 22.47 154.9 22.37 lized1-10-2T 42.2 38.69 266.8 22 151.7 22.92 (trip- 2-1-3T 42.1 37.54 258.821.62 149.1 19.69 licate 2-1-3B 38.09 262.6 22.64 156.1 18.48 results2-5-4T 41.8 37.75 260.3 21.88 150.9 19.66 with 2-10-4T 41.5 38.54 265.722.47 154.9 20.23 left- 2-10-4B 39.06 269.3 23.17 159.8 17.92 over3-1-3T 41.8 39.99 275.7 23.24 160.2 21.4 front, 3-1-3B 39.69 273.7 23.1159.3 21.06 mid- 3-5-4T 41.7 40.38 278.4 22.85 157.6 21.88 dle, 3-5-4B39.99 275.7 23.22 160.1 21.52 and 3-10-5T 41.5 41.1 283.4 23.55 162.422.49 rear 3-10-5B 40.82 281.5 23.55 162.4 21.96 piueces 4-1-1T 41.639.84 274.7 23.76 163.8 22.11 from 4-1-1B 39.66 273.5 23.88 164.7 20.27ex- 4-5-4T 41.6 40.7 280.6 23.99 165.4 22.27 tru- 4-5-4B 40.42 278.724.08 166 21.2 sion) 4-10-3T 41.5 41.2 284.1 24.39 168.2 22.04 4-10-3B40.8 281.3 24.7 170.3 20.85 5-1-2T 41.5 40.4 278.6 23.62 162.9 21.555-1-2B 40.29 277.8 24.02 165.6 21.54 5-5-4T 41.4 41.15 283.7 24.08 16622.69 5-5-4B 40.79 281.2 24.17 166.7 21.17 5-10-2T 41.4 41.65 287.224.48 168.8 22.37 5-10-2B 41.58 286.7 24.56 169.3 21.5 6-1-1T 41.2 41.14283.7 24.29 167.5 22.07 6-1-1B 40.71 280.7 24.12 166.3 20.88 6-5-2T 41.142.07 290.1 24.51 169 22.18 6-5-2B 41.69 287.5 24.69 170.2 21.73 6-10-4T41 42.56 293.5 25.18 173.6 22.76 6-10-4B 42.27 291.5 25.03 172.6 21.537-1-2T 41.4 40.8 281.3 24.09 166.1 21.69 7-5-1T 41.3 41.53 286.3 24.43168.4 21.4 7-5-1B 41 282.7 24.22 167 21.37 7-10-2T 41.2 42.01 289.724.59 169.5 22.14 7-10-2B 41.81 288.3 24.59 169.5 20.98 320/329 4 1-5-5T44.0 47.6 328.2 40.66 280.4 13.57 4 1-5-5B 49.32 340.1 42.37 292.1 15.034 2-10-5T 42.9 47.27 325.9 40.45 278.9 15.54 4 2-10-5B 47.77 329.4 41.54286.4 12.64 4 3-1-1T 43.6 48.63 335.3 43.01 296.6 14.62 4 3-1-1B 48.77336.3 47.53 327.7 8.64 4 4-10-1T 43.7 50.21 346.2 43.6 300.6 14.6 44-10-1B 50.52 348.3 43.82 302.1 16.29 4 5-5-2T 43.5 49.99 344.7 42.95296.1 15 4 5-5-2B 50.29 346.7 43.38 299.1 17.02 4 6-1-3T 43.9 50 344.842.87 295.6 15.35 4 6-1-3B 50.22 346.3 43.65 301 15.31 4 7-1-2T 43.949.9 344.1 42.96 296.2 17.14 4 7-1-2B 50.11 345.5 43.74 301.6 16.04 81-10-4T 45.0 48.7 335.8 44.42 306.3 9.6 8 1-10-4B 49.91 344.1 45.32312.5 12.1 8 2-5-2T 44.9 48.57 334.9 44.78 308.8 11.85 8 2-5-2B 49.64342.3 46.23 318.8 9.78 8 3-5-2T 45.3 51.32 353.9 46.71 322.1 13.15 83-5-2B 51.65 356.1 47.2 325.4 12.67 8 4-10-2T 45.2 52.37 361.1 48.07331.4 12.85 8 4-10-2B 52.67 363.2 48.56 334.8 12.76 8 5-5-1T 45.0 52358.5 47.41 326.9 12.85 8 5-5-1B 52.35 361 47.99 330.9 12.89 8 6-10-2T44.7 52.72 363.5 46.67 321.8 12.98 8 6-10-2B 53.06 365.8 48.76 336.212.9 8 7-5-2T 44.8 52.17 359.7 47.6 328.2 12.34 8 7-5-2B 52.4 361.332.97 227.3 12.84 12 1-10-4T 46.0 49.35 340.3 46.65 321.7 7.16 121-10-4B 50.5 348.2 47.44 327.1 8.08 12 2-1-4T 46.1 49.03 338.1 46.14318.1 10.29 12 2-1-4B 50.39 347.4 47.62 328.3 10.26 12 3-5-1T 46.1 52358.5 47.37 326.6 12.06 12 3-5-1B 52.09 359.2 49.12 338.7 12.08 124-5-1T 46.2 52.64 363 49.5 341.3 11.59 12 4-5-1B 52.73 363.6 49.68 342.511.34 12 5-10-3T 45.7 52.99 365.4 49.98 344.6 10.86 12 5-10-3B 53.31367.6 50.88 350.8 10.87 12 6-5-1T 45.7 53.63 369.8 50.52 348.3 9.91 126-5-1B 53.44 368.5 50.49 348.1 10.94 12 7-10-2T 45.7 53.51 369 50.47 34810.51 12 7-10-2B 53.25 367.2 50.21 346.2 11.37 16 1-10-5T 46.7 50.19346.1 47.15 325.1 8.32 16 1-10-5B 51.21 353.1 48.24 332.6 9.88 16 2-5-2T46.4 49.8 343.4 47.62 328.3 8.45 16 2-5-2B 50.74 349.9 48.69 335.7 8.0516 3-5-1T 46.7 52.34 360.9 49.52 341.4 10.82 16 3-5-1B 52.55 362.3 49.59341.9 11.19 16 4-10-1T 46.8 53.58 369.4 51.22 353.2 9.24 16 4-10-1B53.42 368.3 51.17 352.8 10.84 16 5-1-1T 46.9 52.5 362 50.08 345.3 10.816 5-1-1B 52.52 362.1 50.16 345.9 10.98 16 6-1-2T 46.7 53.03 365.6 50.71349.6 10.71 16 6-1-2B 53.05 365.8 50.74 349.9 10.26 16 7-1-1T 46.9 52.76363.8 50.31 346.9 10.83 16 7-1-1B 52.5 362 50.14 345.7 10.91 338/347 21-5-2T 44.1 47.58 328.1 41.76 287.9 12.23 2 1-5-2B 49.48 341.2 43.67301.1 14.7 2 2-5-3T 43.7 46.88 323.2 41.76 287.9 13.31 2 2-5-3B 48.18332.2 43.27 298.3 10.59 2 3-10-1T 43.8 49.63 342.2 43.9 302.7 13.4 23-10-1B 49.78 343.2 43.59 300.6 14.62 2 4-1-2T 44.3 49.81 343.4 44.45306.5 13.64 2 4-1-2B 49.91 344.1 44.85 309.2 14.56 2 5-5-5T 43.7 50.23346.3 44.18 304.6 13.6 2 5-5-5B 50.37 347.3 45.05 310.6 13.85 2 6-5-4T43.5 50.9 351 44.94 309.9 13.53 2 6-5-4B 51.01 351.7 45.63 314.6 14.24 27-1-4T 44.1 50.41 347.6 44.94 309.9 14.17 2 7-1-4B 50.41 347.6 10.4572.05 14.63 4 1-5-5T 45.2 49.2 339.2 45.25 312 11.45 4 1-5-5B 50.33 34746.31 319.3 10.01 4 2-1-2T 45.5 48.05 331.3 44.68 308.1 10.45 4 2-1-2B49.38 340.5 46.23 318.8 9.15 4 3-5-2T 45.2 50.92 351.1 46.65 321.7 12.624 3-5-2B 51.06 352.1 47.2 325.4 12.87 4 4-5-4T 54.3 51.57 355.6 47.63328.4 12.32 4 4-5-4B 51.62 355.9 48.26 332.8 12.35 4 5-1-3T 45.1 51.3353.7 47.35 326.5 13.09 4 5-1-3B 51.14 352.6 47.48 327.4 12.54 4 6-1-5T45.0 51.89 357.8 45.16 311.4 12.82 4 6-1-5B 51.78 357 48.07 331.4 12.584 7-5-2T 44.9 51.85 357.5 47.72 329 11.93 4 7-5-2B 51.93 358.1 44.44306.4 11.79 6 1-10-1T 46.0 49.14 338.8 46.01 317.2 8.01 6 1-10-1B 50.94351.2 47.38 326.7 10.81 6 2-1-1T 46.2 48.48 334.3 46.01 317.2 8.97 62-1-1B 49.43 340.8 47.02 324.2 8.22 6 3-10-1T 46.0 52.2 359.9 49.27339.7 10.65 6 3-10-1B 52.13 359.4 49.71 342.8 10.61 6 4-1-4T 46.3 51.68356.3 49.05 338.2 11.35 6 4-1-4B 51.56 355.5 49.03 338.1 10.97 6 5-10-1T46.0 52.83 364.3 50.2 346.1 8.78 6 5-10-1B 52.93 365 50.54 348.5 10.1 66-5-4T 46.0 53 365.4 50.62 349 10.29 6 6-5-4B 52.88 364.6 36.49 251.69.97 6 7-10-3T 46.1 52.88 364.6 50.88 350.8 8.64 6 7-10-3B 52.87 364.550.89 350.9 10.36 8 1-5-3T 46.8 49.91 344.1 47.26 325.9 10.72 8 1-5-3B50.82 350.4 47.65 328.5 10.14 8 2-5-4T 46.3 49.44 340.9 47.76 329.3 8.728 2-5-4B 50.38 347.4 48.62 335.2 9.81 8 3-1-2T 46.5 51.2 353 48.87 33710.34 8 3-1-2B 51.14 352.6 48.74 336.1 11.27 8 4-5-1T 46.6 52.05 358.949.59 341.9 10.2 8 4-5-1B 51.94 358.1 49.88 343.9 10.86 8 5-1-3T 46.551.76 356.9 49.6 342 11 8 5-1-3B 51.64 356.1 49.54 341.6 10.53 8 6-10-3T46.4 53.22 367 51.55 355.4 9.8 8 6-10-3B 53.23 367 50.91 351 8.93 87-1-3T 46.5 52.1 359.2 50.16 345.9 9.32 8 7-1-3B 51.82 357.3 49.87 343.99.89 10 1-10-3T 46.7 49.65 342.3 47.6 328.2 8.39 10 1-10-3B 50.81 350.348.52 334.5 10.2 10 2-10-4T 46.3 50.25 346.5 48.88 337 7.05 10 2-10-4B51.11 352.4 48.91 337.2 10.25 10 3-1-2T 46.6 50.95 351.3 48.84 336.89.97 10 3-1-2B 52.03 358.7 50.11 345.5 9.97 10 4-5-5T 46.6 51.83 357.450.11 345.5 9.89 10 4-5-5B 52.24 360.2 50.3 346.8 8.98 10 5-5-2T 46.452.05 358.9 50.2 346.1 9.35 10 5-5-2B 53.17 366.6 51.59 355.7 6.72 106-10-5T 46.6 53.05 365.8 51.65 356.1 8.11 10 6-10-5B 52.51 362.1 50.78350.1 9.09 10 7-5-5T 46.8 52.14 359.5 50.48 348.1 8.66 10 7-5-5B 49.46341 47.8 329.6 6.02 12 1-10-3T 47.3 50.51 348.3 48.39 333.6 9.72 121-10-3B 48.92 337.3 47.68 328.8 6.88 12 2-5-1T 46.9 49.49 341.2 48.07331.4 7.24 12 2-5-1B 50.77 350.1 48.84 336.8 10.28 12 3-1-1T 47.0 50.52348.3 48.6 335.1 9.96 12 3-1-1B 51.91 357.9 50.32 347 9.13 12 4-10-5T47.1 51.6 355.8 50.15 345.8 9.37 12 4-10-5B 51.85 357.5 50.26 346.5 9.0212 5-5-3T 46.8 51.63 356 49.9 344.1 9.35 12 5-5-3B 52.61 362.7 51.29353.6 7.51 12 6-5-3T 46.6 52.33 360.8 51.1 352.3 8.22 12 6-5-3B 52.03358.7 50.62 349 8.06 12 7-5-1T 46.8 51.64 356.1 50.09 345.4 8.59 127-5-1B 49.89 344 48.34 333.3 7.68 356/365 2 1-10-2T 46.2 48.49 334.345.16 311.4 9.67 2 1-10-2B 49.99 344.7 46.6 321.3 9.97 2 2-1-2T 46.547.3 326.1 44.66 307.9 7.91 2 2-1-2B 48.71 335.9 46.13 318.1 8.37 23-1-5T 46.2 50.46 347.9 47.16 325.2 10.68 2 3-1-5B 50.52 348.3 47.47327.3 11.04 2 4-1-5T 46.4 50.88 350.8 47.92 330.4 11.78 2 4-1-5B 50.93351.2 48.19 332.3 10.85 2 5-10-4T 45.9 51.51 355.2 48.45 334.1 10.61 25-10-4B 51.69 356.4 48.9 337.2 10.62 2 6-5-1T 45.8 52.12 359.4 49.13338.8 10.61 2 6-5-1B 52.09 359.2 49.41 340.7 11.32 2 7-5-3T 46.1 51.8357.2 49.07 338.3 10.65 2 7-5-3B 51.83 357.4 49.28 339.8 10.26 4 1-5-4T47.4 49.23 339.4 46.8 322.7 9.8 4 1-5-4B 50.16 345.9 47.51 327.6 10.36 42-1-4T 47.0 48.01 331 46.47 320.4 7.2 4 2-1-4B 49.12 338.7 47.24 325.77.01 4 3-10-4T 47.1 51.8 357.2 49.72 342.8 8.61 4 3-10-4B 51.73 356.749.77 343.2 9.67 4 4-1-5T 47.0 50.98 351.5 49.02 338 9.67 4 4-1-5B 50.94351.2 49.02 338 9.57 4 5-5-1T 46.8 51.82 357.3 49.97 344.5 9.16 4 5-5-1B51.66 356.2 49.85 343.7 9.86 4 6-5-5T 46.7 52.46 361.7 50.88 350.8 7.994 6-5-5B 52.31 360.7 51.01 351.7 8.22 4 7-5-3T 46.9 51.91 357.9 50.21346.2 8.61 4 7-5-3B 51.67 356.3 50.08 345.3 9.81 6 1-10-1T 47.5 48.94337.4 47.35 326.5 7.74 6 1-10-1B 49.89 344 47.82 329.7 9.65 6 2-5-1T47.1 48.41 333.8 47.17 325.2 7.72 6 2-5-1B 48.99 337.8 46.83 322.9 6.216 3-1-4T 47.2 50.33 347 48.53 334.6 9.52 6 3-1-4B 50.18 346 48.43 333.99.8 6 4-10-3T 47.3 51.45 354.7 49.99 344.7 8.32 6 4-10-3B 51.13 352.549.73 342.9 8.55 6 5-10-5T 47.3 51.63 356 50.36 347.2 7.74 6 5-10-5B51.36 354.1 50.17 345.9 8.91 6 6-1-3T 47.1 51.15 352.7 49.7 342.7 8.76 66-1-3B 51 351.6 49.59 341.9 9.11 6 7-1-5T 47.2 50.9 351 49.28 339.8 9.036 7-1-5B 50.72 349.7 49.23 339.4 8.82 8 1-5-1T 48.1 48.09 331.6 45.79315.7 8.1 8 1-5-1B 48.81 336.5 46.24 318.8 9.94 8 2-5-5T 47.5 48.22332.5 47.17 325.2 6.49 8 2-5-5B 48.92 337.3 47.51 327.6 7.04 8 3-5-4T47.6 50.16 345.9 48.46 334.1 8.66 8 3-5-4B 50.13 345.6 48.41 333.8 8.698 4-10-5T 47.7 50.88 350.8 49.62 342.1 8.2 8 4-10-5B 50.65 349.2 42.33291.9 8.86 8 5-5-3T 47.4 50.96 351.4 49.49 341.2 8.55 8 5-5-3B 50.68349.4 49.2 339.2 9.04 8 6-1-1T 47.6 50.67 349.4 49.29 339.9 8.78 86-1-1B 50.49 348.1 49.07 338.3 8.81 8 7-1-4T 47.5 50.45 347.9 48.92337.3 9.01 8 7-1-4B 50.25 346.5 48.76 336.2 8.07 10 1-5-2T 48.2 47.72329 45.38 312.9 9.55 10 1-5-2B 48.08 331.5 45.32 312.5 9.06 10 2-10-5T47.5 48.64 335.4 47.55 327.9 7.7 10 2-10-5B 48.8 336.5 46.15 318.2 7.8410 3-10-2T 47.7 50.73 349.8 49.13 338.8 6.64 10 3-10-2B 50.42 347.648.91 337.2 8.52 10 4-1-3T 47.6 49.16 339 47.43 327 9.29 10 4-1-3B 49.02338 47.32 326.3 8.9 10 5-10-5T 47.7 50.73 349.8 49.49 341.2 7.98 105-10-5B 50.5 348.2 49.22 339.4 7.94 10 6-1-4T 47.6 50.17 345.9 48.77336.3 8.71 10 6-1-4B 49.91 344.1 48.51 334.5 8.38 10 7-1-5T 47.7 49.91344.1 48.41 333.8 8.56 10 7-1-5B 49.58 341.9 48.04 331.2 8.5 374/383 11-5-3T 46 48.34 333.3 45.33 312.6 9.47 1 1-5-1T 46.2 48.36 333.4 45.19311.6 10.18 1 2-1-3T 45.9 47.02 324.2 44.78 308.8 7.41 1 2-1-3B 48.25332.7 45.72 315.2 7.68 1 3-5-3T 46.2 50.63 349.1 47.79 329.5 9.89 13-5-3B 50.56 348.6 47.85 329.9 10.58 1 4-1-3T 46.2 50.37 347.3 47.89330.2 10.8 1 4-1-3B 50.31 346.9 47.75 329.2 11.01 1 5-5-5T 45.9 51.37354.2 48.63 335.3 10.59 1 5-5-5B 51.31 353.8 48.8 336.5 10.78 1 6-1-4T46 51.36 354.1 48.94 337.4 10.34 1 6-1-4B 51.41 354.5 49.14 338.8 10.691 7-1-2T 46.3 51.11 352.4 48.65 335.4 10.32 1 7-1-2B 50.9 351 48.52334.5 9.99 2 1-5-4T 47.6 48.55 334.8 46.32 319.4 7.73 2 1-5-4B 49.42340.8 46.87 323.2 7.83 2 2-5-3T 46.9 48.35 333.4 47.06 324.5 7.44 22-5-3B 48.82 336.6 47.44 327.1 7.51 2 3-1-5T 46.9 50.34 347.1 48.29 3339.11 2 3-1-5B 50.18 346 48.2 332.3 10.33 2 4-1-2T 46.9 50.43 347.7 48.6335.1 9.03 2 4-1-2B 50.34 347.1 48.5 334.4 9.75 2 5-1-4T 47.1 50.92351.1 49.1 338.5 9.72 2 5-1-4B 50.76 350 49.02 338 9.76 2 6-10-4T 46.752.44 361.6 50.86 350.7 7.5 2 6-10-4B 52.37 361.1 50.97 351.4 8.91 27-10-5T 46.8 52.16 359.6 50.95 351.3 7.14 2 7-10-5B 51.98 358.4 50.65349.2 8.97 3 1-10-5T 47.8 48.32 333.2 46.76 322.4 5.61 3 1-10-5B 49.45341 47.47 327.3 7.56 3 2-5-5T 47.3 48.23 332.5 47.09 324.7 6.59 3 2-5-5B49.11 338.6 47.59 328.1 6.98 3 3-1-3T 47.5 49.94 344.3 48.17 332.1 9.053 3-1-3B 49.88 343.9 48.1 331.6 9.25 3 4-5-2T 47.4 50.59 348.8 49 337.99.07 3 4-5-2B 50.4 347.5 48.82 336.6 8.63 3 5-10-2T 47.3 51.59 355.750.3 346.8 7.4 3 5-10-2B 51.42 354.5 50.13 345.6 9.14 3 6-5-5T 46.951.61 355.9 50.4 347.5 7.29 3 6-5-5B 51.38 354.3 50.2 346.1 8.68 37-1-3T 46.8 50.55 348.5 49.04 338.1 9.09 3 7-1-3B 50.22 346.3 48.73 3368.82 4 1-5-1T 47.7 47.86 330 45.56 314.1 8.78 4 1-5-1B 48.35 333.4 45.71315.2 8.18 4 2-5-4T 47.2 48.07 331.4 46.98 323.9 7.98 4 2-5-4B 48.4333.7 46.98 323.9 7.35 4 3-10-3T 47.4 50.53 348.4 49.07 338.3 6.58 43-10-3B 50.32 347 48.81 336.5 8.26 4 4-1-1T 47.4 49.25 339.6 47.54 327.89.36 4 4-1-1B 49.1 338.5 47.42 327 9.36 4 5-1-1T 47.5 49.76 343.1 48.2332.3 8.98 4 5-1-1B 49.39 340.5 47.8 329.6 8.88 4 6-10-2T 47.2 51.65356.1 50.67 349.4 6.53 4 6-10-2B 51.16 352.7 49.96 344.5 7.61 4 7-1-1T47.3 49.75 343 48.25 332.7 8.42 4 7-1-1B 49.35 340.3 47.79 329.5 8.78 51-10-2T 47.8 47.52 327.7 46.2 318.5 5.95 5 1-10-2B 48.31 333.1 46.26 3197.63 5 2-10-2T 47.3 48.28 332.9 47.14 325 7.88 5 2-10-2B 48.56 334.847.19 325.4 6.79 5 3-10-2T 47.6 50.26 346.5 48.73 336 6.71 5 3-10-2B49.97 344.5 48.46 334.1 8.42 5 4-5-3T 47.5 49.71 342.8 48.18 332.2 8.495 4-5-3B 49.29 339.9 47.68 328.8 8.17 5 5-10-1T 47.4 50.65 349.2 49.4340.6 6.06 5 5-10-1B 50.51 348.3 49.14 338.8 7.82 5 6-1-5T 47.5 49.92344.2 48.52 334.5 8.3 5 6-1-5B 49.66 342.4 48.24 332.6 8.18 5 7-5-5T47.4 50.04 345 48.66 335.5 7.72 5 7-5-5B 49.58 341.9 48.13 331.9 7.88 61-5-3T 48.3 46.11 317.9 43.65 301 7.99 6 1-5-3B 46.29 319.2 43.16 297.68.65 6 2-10-3T 47.6 47.32 326.3 46 317.2 7.18 6 2-10-3B 47.4 326.8 45.96316.9 6.65 6 3-10-3T 47.9 49.2 339.2 47.58 328.1 7.54 6 3-10-3B 48.76336.2 47.13 325 8.25 6 4-10-4T 48 49.09 338.5 47.56 327.9 8.78 6 4-10-4B48.81 336.5 47.18 325.3 8.47 6 5-5-4T 47.7 49.12 338.7 47.52 327.7 8.396 5-5-4B 48.74 336.1 47.08 324.6 7.81 6 6-10-5T 47.6 50.64 349.2 49.14338.8 6.24 6 6-10-5B 50.19 346.1 48.91 337.2 7.7 6 7-10-4T 47.7 50.09345.4 48.83 336.7 6.92 6 7-10-4B 49.57 341.8 48.17 332.1 7.99

The tensile properties for this section versus that of section 569310show that there is a little difference between ultimate tensile strengthand yield strength with the elongation being slightly different.

The artificial age practices that called for higher temperatures andshorter times displayed over-aging. Where section 569310 had both itstensile and yield strength drop off, section 569510 had only the tensilestrength drop with the yield strength lingering at elevated strengthswhich is not common. Upon inspecting the collected data in Table 5 and7, it was determined that the cause of the out-of-the-ordinary yieldstrengths was due to the sampling locations. Section 569310 had the samelocation from every charge tested while section 569510 was morerandomized—sampling from front, middle, and rear sections rather thanusing the same location for every condition.

Despite section 569510 being fully recrystallized, section 569310experienced better elongation. This could be due to the unrecrystallizedgrain structure in the center wall. In other words, there were notenough coarse recrystallized grains to interfere with the elongation.The inventive chemistry described here was created to avoid the issue ofpoor elongation resulting from coarse grains along the edges, but due tothe die design of section 569310, the unrecrystallized portions wereunavoidable with the extrusion process used.

Example 5 Metallurgical Results—Ingot

Sample slices were taken from one log of Example 1 after homogenizationfor characterization purposes. One slice was taken from the head (top)and the other was taken from the butt (bottom) of the log. Two microswere mounted from each slice; one along the edge in the transversedirection and one from the center in the longitudinal direction withrespect to the casting direction. Images of the as-polished pieces areshown in FIGS. 16A, 16B, 17, 18A, 18B, and 19.

After the as-polished micro images were taken, the micros were thenetched electrolytically to further define the grain structure.Electrolytic etched images of the micros are shown in FIGS. 20-23.

Example 6 Metallurgical Results—Extrusion

Sample sections are taken from various charges of Example 2. Section569510 display fine grain recrystallization while section 569310exhibits a mixed grain structure of unrecrystallized and coarse grains.

The extruded grain structure for section 569310 is shown in FIGS. 24 and25. The grain structure for pieces extruded through section 569510 isshown in FIGS. 26 and 27.

Images containing electrolytically etched samples from both sections arelocated in FIGS. 28 and 29. The coarse grain recrystallization along theedges and weld is more evident for section 569310. The fine grainstructure for section 569510 is also more visible.

Example 7 Metallurgical Results—Weld Integrity

The welds of each piece were inspected. Section 569510 showed signs oftransverse welds in the front samples. The image of the transverse weldis shown in FIG. 30. The transverse welds were not present in the middlesamples inspected, and it was determined that the front trim for theextruded length was not enough to vanquish the weld. The front trim waschanged from twelve feet to fourteen feet to counteract it.

Section 569310 showed signs of bad welds in the center walls as shown inFIG. 31. There is clear separation across the weld. The bad weld in thecenter wall was found in front, middle, and rear samples of chargesfour, five, and six, and in front and middle sections of charge seven.Since the bad weld was present in a significant amount of samples, itwas determined that the design of the die was the most likely cause forthe occurrence. Though the weld did not affect testing for this example,the die would need to be redesigned to prevent the bad weld fromoccurring.

Example 7 Grain Structure and Die Design

When extruding two similar sections with the same alloy, it is importantto note the differences, if any, in the design of the dies that wereused. The two sections (569310 and 569510) were run through the extruderat similar speeds and temperatures (as shown in Example 2 above) but hadvery different grain structures (as shown in Example 6 above).

The die design for section 569310 is shown in FIG. 32; the die designfor section 569510 is shown in FIG. 33. There were a few dissimilaritiesbetween the dies. The die for section 569310 contains four ports for thealuminum to flow through as well as a six degree choke around theoutside of the shape. In contrast, the die for section 569510 has fiveports and no choke. Both choke and the number of ports have an effect onthe recrystallization process.

The choke plays a big role in recrystallization of grains—specificallythe lack of recrystallization. A choke helps to ease metal through thedie which, in turn, causes less strain energy to be present. Grains willnot recrystallize from the as-cast structure if there is not enoughenergy to do so. This lack of energy is what caused the unrecrystallizedregions in section 569310 (FIG. 1) which had a six degree choke on theoutside of the shape (FIG. 32). Section 569510 (FIG. 2) in comparisondoes not have any choke present (FIG. 33). The absence of choke (forexample for section 569510) will increase the strain energy as the metalis pushed through, which could explain the recrystallization in theouter walls.

The number of ports present in the die design impacted the shapes alittle differently. The extra fifth port on section 569510 is nearlytwice the size of the other four, which caused metal to flow through itmore freely and a little easier. The aluminum wanted to take this pathbecause there is less resistance for it to flow. This increased themetal flow through the center which then increased the shear stresses inthe metal. Increased shear stresses give the metal more energy that isnecessary to recrystallize, so the entire center wall was able torecrystallize.

The compositions for the additives including at least chromium andmanganese, as well as the extrusion practice, helped the alloy torecrystallize upon extruding through section 569510.

Example 8 Mechanical Properties—Extrusion Processing Effects

The process run for the sections in Example 2 showed that billet andexit temperatures as well as extrusion speeds (Table 3 above) wereacceptable and provided the appropriate amount of strength to the alloy.The billet temperatures were such to ensure that the material had theability to extrude easily. The exit temperatures were set so that theMg₂Si precipitates that were present dissolved. The speeds were as fastas the material could handle without tearing the material as well asmake sure that the metal made it into quench so that the Mg₂Si could notprecipitate out after it was dissolved.

The exit temperatures of each section of Example 2 during extrusionvaried depending on the charge. The first charges of both sections had alower exit temperature than the other five. This negatively impacts thestrength of the metal. The lower exit temperatures cause the Mg₂Siprecipitates to not dissolve completely which will cause them to becomecoarse and further apart from each other which allow more dislocationsto move through the piece. FIG. 34 shows the yield strength as afunction of exit temperature for the artificial age practice 338/347° F.for six hours for section 569310. Charges one and two experienced alower strength than the rest of the group because of the lower exittemperature. Due to this drop in strength the first two charges werediscarded from testing results.

Example 9 Comparison

The artificial aging practice of 338/347° F. for six hours described inExample 4 was determined to be the best choice compared with all of theother conditions described in Examples herein. The average yieldstrength for section 569310 and section 569510 at this time andtemperature was between 330 and 335 MPa—above the minimum requirement of320 MPa. The elongation for section 569310 had an average of 12% and theelongation for section 569510 was 10%. Though the elongation was not arequirement it is a benefit to the material. Using this age practice,HS6X has the ability to act as a suitable substitute to the 7003aluminum alloy for automotive development.

Example 10

The following embodiments are meant to be illustrative and propheticonly. Values are displayed in weight percents, with the balance aluminumunless otherwise stated.

In a first embodiment, one HS6X composition is as follows:

Others Others Si Fe Cu Mn Mg Cr Zn Ti Each Total 0.9- 0.5 0.05- 0.750.7- 0.25 0.05 0.10 0.05 0.15 1.2 max 0.30 max 1.0 max max max

In a second embodiment, one HS6X composition is as follows:

Si Fe Cu Mn Mg Cr Zn Ti 1.05- 0.25 0.09- 0.51- 0.74- 0.01 0.02 0.04 1.10max 0.15 0.56 0.80 max max max

In a third embodiment, one HS6X composition is as follows:

Si Fe Cu Mn Mg Cr Zn Ti 1.05- 0.25 0.12- 0.15- 0.76- 0.03 0.05 0.04 1.12max 0.18 0.20 0.82 max max max

In a fourth embodiment, one HS6X composition is as follows:

Si Fe Cu Mn Mg Cr Zn Ti 1.05- 0.25 0.12- 0.15- 0.75- 0.25 0.05 0.04 1.12max 0.18 0.75 0.82 max max max

While the present inventions have been illustrated and described in manyembodiments of varying scope, it should be understood that suchdisclosures have been presented by way of example only and are notlimiting—variations may be made within the spirit and scope of theinventions. Accordingly, it is intended that the scope of the inventionsset forth in the appended claims not be limited by any specific wordingin the foregoing description and above-described exemplary embodiments.

What is claimed:
 1. An aluminum alloy comprising: about 0.90 to about1.2 weight percent silicon, up to about 0.5 weight percent iron, about0.05 to about 0.30 weight percent copper, up to about 0.75 weightpercent manganese, about 0.70 to about 1.00 weight percent magnesium, upto about 0.25 weight percent chromium, up to about 0.05 weight percentzinc, up to about 0.10 weight percent titanium, and the balanceconsisting essentially of aluminum.
 2. An alloy of claim 1 wherein eachof the elements may vary by about 10%.
 3. An alloy of claim 1 having afine grain structure.
 4. An alloy of claim 1 comprising up to about 0.03weight percent chromium.
 5. An alloy of claim 1 comprising up to about0.20 weight percent manganese.
 6. An alloy of claim 1 comprising up toabout 0.15 weight percent impurities.
 7. An alloy of claim 1 comprising:about 1.13 weight percent silicon, about 0.17 weight percent iron, about0.16 weight percent copper, about 0.21 weight percent manganese, about0.80 weight percent magnesium, about 0.004 weight percent chromium,about 0.006 weight percent zinc, about 0.014 weight percent titanium,and the balance consisting essentially of aluminum.
 8. An alloy of claim7 having a fine grain structure.
 9. An alloy of claim 7 comprising up toabout 0.15 weight percent impurities.
 10. An extrusion that has a finegrain structure, the extrusion comprising: about 0.90 to about 1.2weight percent silicon, up to about 0.5 weight percent iron, about 0.05to about 0.3 weight percent copper, up to about 0.75 weight percentmanganese, about 0.70 to about 1.0 weight percent magnesium, up to about0.25 weight percent chromium, up to about 0.05 weight percent zinc, upto about 0.1 weight percent titanium, and the balance consistingessentially of aluminum.
 11. An extrusion of claim 10 wherein theextrusion has a tensile yield strength of at least about 290 MPa and anultimate tensile strength of at least about 310 MPa.
 12. An extrusion ofclaim 10 wherein the extrusion has a thickness of about 0.050 inch toabout 0.500 inch.
 13. An extrusion of claim 10 wherein the extrusion isa 6XXX aluminum alloy.
 14. An extrusion of claim 10 wherein each of theelements may vary by about 10%.
 15. An extrusion of claim 10 comprisingup to about 0.03 weight percent chromium.
 16. An extrusion of claim 10comprising up to about 0.20 weight percent manganese.
 17. An extrusionof claim 10 comprising up to about 0.15 weight percent impurities.
 18. Amethod of forming aluminum comprising: extruding an initial aluminumbillet at an initial billet temperature of at least about 800° F.through a press at an extrusion speed of at least about 40 feet perminute; and obtaining an extruded aluminum material at an exittemperature greater than the initial billet temperature.
 19. A method ofclaim 18 further comprising water quenching the extruded aluminummaterial.
 20. A method of claim 18 further comprising heating theextruded aluminum material to about 340° F. for about six hours.
 21. Amethod of claim 18 where the extruded aluminum material has a tensileyield strength of at least about 320 MPa.
 22. A method of claim 18 wherethe extruded aluminum material has a fine grain structure.
 23. A methodof claim 18 where said initial aluminum billet is an alloy comprising:about 0.90 to about 1.2 weight percent silicon, up to about 0.5 weightpercent iron, about 0.05 to about 0.3 weight percent copper, up to about0.75 weight percent manganese, about 0.70 to about 1.0 weight percentmagnesium, up to about 0.25 weight percent chromium, up to about 0.05weight percent zinc, up to about 0.1 weight percent titanium, and thebalance consisting essentially of aluminum.
 24. An method of claim 23where said alloy comprises up to about 0.03 weight percent chromium. 25.An method of claim 23 where said alloy comprises up to about 0.20 weightpercent manganese.
 26. An method of claim 23 where said alloy comprisesup to about 0.15 weight percent impurities.